Technical field [0001]CROSS REFERENCE TO RELATED APPLICATIONS This application is based on Japanese Patent Application No. 2017-073578, filed in Japanese on April 3, 2017, and claims priority, the contents of which are incorporated herein. [0002]The present invention is, for example, hat-shaped steel sheet pile, methods and manufacturing equipment production of steel sheet pile having a flange, such as U-shaped steel sheet piles. BACKGROUND [0003] 　Conventionally, the manufacture of steel sheet pile having a joint at both ends, such as hat-type is done by the grooved rolling. The general steps of this caliber rolling method, a rectangular material first in a heating furnace and heated to a predetermined temperature, rough rolling mill having a caliber, be rolled in order by the intermediate mill and finish rolling mill known It is. As example, Patent Document 1 caliber rolling method, rough rolling, and arranging a plurality of grooved to roll in the intermediate rolling and finish rolling, a hat-shaped steel sheet pile performing rolling by 1-2 pass in their respective grooved production techniques have been disclosed. [0004] 　Further, for example, Patent Document 2, constitutes the caliber as stretching balance of the web and the flange is maintained in the production of U-shaped steel sheet piles, a rolling a plurality of times by reciprocating the material to be rolled in the same grooved in a technique of performing is disclosed. Further, for example, Patent Document 3, a technique that aims to reduce the pouring resistance during construction of the steel sheet pile is disclosed configuration provide a gentle slope portion on the flange portion it has been proposed. [0005] 　Further, for example, Patent Document 4, and two flanges / web transition section parallel to the rolling plane, Z-shaped steel having a step of forming a preform having a central section that is inclined relative to the rolled surface in the neutral line near manufacturing technology sheet pile (sheet pile) has been disclosed. [0006] 　Thus, and hole-type rolling method as the manufacturing method of the steel sheet pile, a technique for rolling back and forth several times a material to be rolled (so-called 1-hole type multi-pass rolling) has been developed conventionally in the same caliber. CITATION Patent Document [0007] Patent Document 1: JP 2006-88176 JP Patent Document 2: JP 60-44101 Patent Publication Patent Document 3: JP 2004-76580 JP Patent Document 4: JP-A 8-224634 JP Summary of the Invention Problems that the Invention is to Solve [0008] 　However, in the conventional caliber rolling method illustrated in Patent Document 1, the rough rolling, at an intermediate rolling process - finishing rolling step, 1-2 path 1 grooved flange as a linear state of approximately the same angle as the product performs the rolling, especially when the flange width is large plate thickness is thin, not take stretching balanced for each site at the performing reverse rolling in the cross section of the rolled material, may flanges wave occurs is there. The "hole-type" in this specification, in which is formed between the upper and lower grooved roll gap, a partial rolling passes the material to be rolled. In the following, even if the distance between the upper and lower grooved roll varies, if the same groove on the roll to form a hole-type, it is referred to as the hole-type "identity grooved". Further, the "reverse rolling" in the present specification, in the same caliber formed by the upper and lower grooved roll, it from the step of repeatedly rolling back and forth multiple paths the rolled material while gradually narrowing the roll gap it is. [0009] 　In the technique described in Patent Document 2, as a hat-shaped steel sheet pile, particularly when the flange width than conventional was conducted rolled like a large stretching against large flange is thin large sheet piles to, even maintaining the balance of stretch described in Patent Document 2, shape defects occur, such as flanges waves, it is difficult to stably rolled and shaped, there is a possibility that the product shape defect occurs. Further, it may fail to achieve proper balance conditions for suppressing the occurrence of shape defect of the flange waves such as in a rolling mill constraints. Recently, that has been required is economy and workability of the steel sheet pile of the thin large sectional height of greater thickness in view, further improvement in technology in the production of such large sheet piles are required it is a reality. [0010] 　In the technique described in Patent Document 3, at least one portion of the central portion a portion (corner portion is formed by the end flange and the web portion and the web portion of the web portion (defined as the flange portion in the present invention) by providing a gentle slope portion above), although the description to the effect that improves the workability and reduces the pouring resistance is not been any mention of shape defect of the flange waves and the like in the manufacturing process, large steel sheet pile suppression of shape in manufacturing defects, improvement of the stability further technical relates realization of rolling and shaping the like has is demanded. [0011] 　The technique described in Patent Document 4 is presumed to be a technique of performing a hole-type one-pass rolling is performed multiple passes rolling gradually narrowing the upper and lower roll gap at the same caliber, so-called reverse a description that carry out the rolling is not. This, in the technique described in Patent Document 4, when performing a reverse rolling with the same caliber, it stretching uneven for each region in the cross section, the charging status of the joint portion is changed in metal flow occurs in addition, the stretching of the flange / web transition sections geometrically larger than the extension of the central section, twist that is likely to occur is thought to be the reason. When performing the one-hole type one-pass rolling, it is possible to an optimum shape hole shape during one pass rolling, a problem shape defect of the rolled material due to the pore shape can not occur. That is, in Patent Document 4, has not been any mention of the occurrence of the flange waves which may occur during reverse rolling, of course, do not mention also the suppression of the flange wave. [0012] 　In view of the above circumstances, an object of the present invention is to suppress a defective shape of the flange waves and the like due to the reverse rolling occurs, steel having a flange capable of improving the stability of the product dimensional accuracy and rolled It is to provide a manufacturing technology of sheet piles. Means for Solving the Problems [0013] 　To achieve the above object, according to the present invention, a manufacturing method of forming a steel sheet pile having a flange from the rolled material by grooved rolling, reverse with respect to the material to be rolled by the same caliber comprising a step of performing rolling, the step of performing the reverse rolling includes the step of forming a first flange portion which straddles the neutral line, the second and third flange portions disposed on both sides of the first flange portion the caliber has a first flange face portion to form a first flange portion, and a second flange opposing portion to form a second flange portion, for forming the third flange portion includes a third flange facing portion, and relative to the horizontal plane, the inclination angle of the first flange facing portion may be greater than the inclination angle of the second and third flange facing portion, have a flange Method for producing a steel sheet pile is provided that. [0014] 　Step of performing the reverse rolling, and the web handling section includes the step of forming the arm corresponding portion, the hole type, and the web face portion to form a web handling unit, for forming the arm corresponding portion of the arm facing portion, wherein the hole type, the the web-side flange facing subgroup the second flange facing portion comprising at least one, said third flange facing portion at least one comprising an arm side flange facing subgroup When, and a boundary portion between the said web-side flange facing subgroup web facing portion, with respect to a straight line connecting the boundary portion between the arm-side flange portion facing unit and the arm opposed portion, the second flange facing portion is convex toward the flange outwardly, the third flange facing portion may be convex toward the flange inwardly. [0015] 　In the above-grooved flange stretching λf1 in the first flange portion, the flange extending λf2 in the second flange portion and the third flange portion, a small rolling may be performed than Ramudaefu3. [0016] 　Said first flange portion, a second flange portion, and forming a third flange portion may be an intermediate rolling process. [0017] 　The caliber may have a hole shape which both ends in the width direction is open. [0018] 　It said first flange portion, a second flange portion, and a flange corresponding portion of the bent shape formed on the rolled material by the step of forming the third flange section, the desired flatness by rolling in the subsequent caliber of the process shape may be rolled modeling. [0019] 　In the above-grooved flange stretching λf1 in the first flange portion is rolled so that the following web stretching λw may be performed. [0020] 　The steel sheet pile may be a hat-shaped steel sheet pile. [0021] 　According to the present invention from another aspect, a manufacturing facility to form a steel sheet pile having a flange from the rolled material by grooved rolling, to reverse rolling with respect to the material to be rolled by the same caliber comprising a rolling mill, rolling mill to perform the reverse rolling includes a first flange portion which straddles the neutral line, the caliber of forming the second and third flange portions disposed on both sides of the first flange portion , the hole type, and a first flange face portion to form a first flange portion, and a second flange opposing portion to form a second flange portion, for forming the third flange portion a third flange facing portion comprises, relative to the horizontal plane, the inclination angle of the first flange facing portion may be greater than the inclination angle of the second and third flange facing portion, the steel arrows having a flange Manufacturing facilities are provided. [0022] 　Rolling mill to perform the reverse rolling, forming a web corresponding section, includes a grooved to form the arm corresponding portion, the hole type, and the web face portion to form a web handling section, the arm corresponding portion and a arm portion opposed to the hole type, the second flange facing portion at least one comprising a web flange facing subgroup, the third flange facing portion of the arm-side flange facing comprising at least one comprises a subgroup, and a boundary portion between said web-side flange facing subgroup and said web opposing portions, relative to a straight line connecting the boundary portion between the arm-side flange portion facing unit and the arm facing portion, said second flange facing portion is convex toward the flange outwardly, the third flange facing portion may be convex toward the flange inwardly. [0023] 　In the grooved flange stretching λf1 in the first flange portion, the flange extending λf2 in the second flange portion and the third flange portion may be smaller than Ramudaefu3. [0024] 　The caliber may be a grooved provided in an intermediate rolling mill. [0025] 　The caliber may have a hole shape which both ends in the width direction is open. [0026] 　It said first flange portion, a second flange portion, and, subsequent holes rolling shaping a flange corresponding portion of the bent shape formed on the rolled material by rolling in the caliber of forming the third flange portion to the desired flat shape it may be provided with a mold. [0027] 　In the grooved flange stretching λf1 in the first flange portion may be equal to or less than the web stretching lambda] w. [0028] 　The steel sheet pile may be a hat-shaped steel sheet pile. The invention's effect [0029] 　According to the present invention, by suppressing the defective shape of the flange waves and the like due to the reverse rolling occurs, it is possible to improve the stability of the product dimensional accuracy and rolling. BRIEF DESCRIPTION OF THE DRAWINGS [0030] FIG. 1 is a schematic illustration of a rolling line. FIG. 2 is a schematic sectional view showing a first grooved grooved shape. 3 is a schematic sectional view showing a second grooved grooved shape. 4 is a schematic sectional view showing a third grooved grooved shape. 5 is a schematic sectional view showing a fourth grooved grooved shape. 6 is a schematic sectional view showing a fifth grooved grooved shape. [Figure 7] is a grooved schematic illustration of the configuration of the third hole type is improved, a schematic overall view (a), the enlarged view of the vicinity portion facing the flange corresponding portion (b) show. 8 is a schematic diagram according to a modification of the present invention. 9 is an explanatory diagram of embodiment. It is a schematic explanatory view according to a modification of FIG. 10 the present invention. 11 is a schematic diagram according to a modification of the present invention. It is a schematic explanatory view according to a modification of FIG. 12 the present invention. DESCRIPTION OF THE INVENTION [0031] 　It will be described below with reference to the drawings, embodiments of the present invention. In the specification and drawings, components having substantially the same function and structure are a repeated explanation thereof by referring to the figures. Incidentally, the material to be rolled substantially hat-shaped steel sheet pile shape in the present embodiment will be described as being rolled in a posture in which the web is positioned below the flange (so-called U posture), but of course the scope of the present invention also extends to rolling in the other position (e.g., inverted U position). Moreover, the scope of the present invention is a steel sheet pile product having hat-shaped, the various flanges, such as U-shaped steel sheet pile product manufactured in the present embodiment will be described as a hat-shaped steel sheet pile product . [0032] 　In addition, the material to be rolled A described below, shows a steel to be rolled in the production of the hat-shaped steel sheet pile products are collectively steel is Tsuzai on rolling line L to be rolled material A was called, it is described separately different designations as necessary for the material to be rolled a in a state of being pressure in each of the rolling mill (A1 ~ A5 described below). The material to be rolled A has a substantially hat-shape, the web handling section 3 is substantially horizontal and a flange corresponding portion 5, 6 are connected with a predetermined angle at both ends of the web corresponding section 3, corresponding each flange an arm corresponding portion 8, 9 are connected to the connection side and different ends of the web corresponding section 3 in parts 5 and 6, composed from the joint correspondence portions 10 and 11 which are connected to the distal end of the arm corresponding portion 8,9 It is. The end portion of the fitting corresponding portions 10 and 11 is referred to as a claw portion 14, 15 respectively. In the following, the different parts of the material to be rolled A, shown in the above code, it will be described. 　In the present specification relates to the material to be rolled A, the rolling direction is referred to as a "longitudinal direction" of the material to be rolled, a direction parallel to and perpendicular to the longitudinal direction and the rolling roll axis of the rolled material "width direction" and referred, it will be described referred to the direction perpendicular to both the longitudinal direction and the width direction as a "height direction" of the material to be rolled. Further, the "Thickness reduction" of the material to be rolled, shows a thickness reduction with respect to the thickness direction of the material to be rolled. [0033] 　First, outline of the rolling line L as a manufacturing apparatus 1 for manufacturing a hat-shaped steel sheet pile which is a basic configuration. Figure 1 is a rolling line L to produce a hat-shaped steel sheet pile, it is an explanatory diagram of a rolling mill or the like provided in the rolling line L. Rolling the traveling direction of the rolling line L in FIG. 1 is a direction indicated by arrows, the material to be rolled A flows to the direction, the roughing mill for explaining the grooved rolling mill on line (below, intermediate rolling machine, is rolling out in the finishing mill), the product is shaped. The plurality of conveying rolls (not shown) on the rolling line L is installed, the material to be rolled A by those conveyor roll is conveyed on the rolling line L. [0034] 　As shown in FIG. 1, the rolling line L, rolling upstream from the order roughing mill (BD) 17, a first intermediate mill (R1) 18, a second intermediate mill (R2) 19, finishing mill ( F) 30 is disposed. [0035] 　In rolling line L shown in FIG. 1, the heated e.g. slab in a heating furnace, not shown (located on the rolling line L upstream), the material to be rolled A bloom etc., sequentially rolled in rough rolling mill 17 to the finishing mill 30 hat-type steel sheet pile as a final product by being is produced. [0036] 　Next, rough rolling mill 17 arranged on the rolling line L, the first intermediate rolling mill 18, the second intermediate rolling mill 19, the drawing order from the upstream side for the hole shape of which is provided to one of the finish rolling mill 30 It will be briefly described with reference. In the following Figure 2-6 for reference in the description illustrates a cross section of the rolled material A when the pressure in each hole type for reference is completed by one-dot chain line. [0037] 　2, the first hole-type 49 (hereinafter, simply both caliber 49 wherein) is a schematic sectional view showing a hole shape of. As shown in FIG. 2, caliber 49, the upper grooved roll 45, constituted by the lower grooved roll 48. These on grooved rolls 45 and the lower grooved roll 48 caliber 49 constituted by is provided roughing mill 17 for example, a thickness reduction with respect to the total material to be rolled A by grooved rolling in caliber 49 (i.e., rough rolling) is carried out. Specifically, substantially hat-shaped caliber, such as close to a shape rolling the heated slab or the like to a predetermined temperature is carried out in a heating furnace, rough profiles A1 is shaped as shown in dashed line in FIG. Incidentally, the rough rolling at this time, may be performed by reverse rolling for example in the same caliber 49. [0038] 　Further, FIG. 3 is a schematic sectional view showing a hole shape of the second grooved 59 (hereinafter, simply caliber 59 both described). As shown in FIG. 3, the caliber 59 includes an upper grooved roll 55, constituted by the lower grooved roll 58. These on grooved rolls 55 and the grooved 59 formed by the lower grooved roll 58 is provided on the first intermediate rolling mill 18, for example, a thickness reduction with respect to the total material to be rolled A by grooved rolling in caliber 59 ( that is, the first intermediate rolling) is carried out. Pressure to align the pawl height of the grooved 59 simultaneously claw portions 14, 15 and the thickness reduction in the desired height is also made, in particular, further hat-shaped coarse profile A1 taken out from the grooved 49 caliber as close to the shape rolling is performed. Thus, the first intermediate member A2 shown in dashed line in FIG. 3 is shaped. Incidentally, the rolling here, for example, carried out by reverse rolling in the same caliber 59. [0039] 　Further, FIG. 4 is a schematic sectional view showing a hole shape of the third grooved 69 (hereinafter, simply caliber 69 both described). As shown in FIG. 4, the caliber 69 includes an upper grooved roll 65, constituted by the lower grooved roll 68. These on grooved rolls 65 and the grooved 69 formed by the lower grooved roll 68 is provided on the second intermediate rolling mill 19, for example, a thickness reduction with respect to the total material to be rolled A by grooved rolling in caliber 69 ( that is, the second intermediate rolling) is carried out. Specifically, further caliber as close to a hat shape rolling a first intermediate member A2 taken out from the grooved 59 is performed, the second intermediate member A3 shown in dashed line in FIG. 4 is shaped that. Therefore the caliber 69 has a shape that both end portions in the width direction is open, the claw portions 14, 15 of the rolled material A has a shape that extends in the width direction by the thickness reduction. Incidentally, the rolling here, for example, carried out by reverse rolling in the same caliber 69. [0040] 　Figure 5 is a schematic sectional view showing a hole shape of the fourth grooved 79 (hereinafter, simply caliber 79 both described). As shown in FIG. 5, the caliber 79, the upper grooved roll 75, constituted by the lower grooved roll 78. These on grooved rolls 75 and the grooved 79 formed by the lower grooved roll 78 is provided on the second intermediate rolling mill 19, for example, forming the claw portions 14, 15 of the said grooved 79 example be rolled material A is It is intensively carried out. More specifically, the second intermediate member A4 reduction is carried out such that the molding is shaped pawl height of the third grooved states extended by 69 claw portions 14 are aligned to the desired height . Incidentally, the rolling here may be one for reduction of thickness. [0041] 　Also, FIG. 6 is a schematic sectional view showing a hole shape of the fifth hole type 89 (hereinafter, simply caliber 89 both described). As shown in FIG. 6, the caliber 89, the upper grooved roll 85, constituted by the lower grooved roll 88. Caliber 89 constituted by these upper grooved roll 85 and the lower grooved roll 88 is provided on the rolling mill 30 finishing example, predominantly bending of the claw portions 14, 15 with respect to the rolled material A by the grooved 89 forming (i.e., finish rolling) is carried out. Specifically, pressure of the second intermediate member A4 and finish A5 substantially hat-shape (substantially hat-shaped steel sheet pile product shape) is performed. Incidentally, finish rolling is usually not performed in reverse rolling is performed in the rolling of only one pass. [0042] 　Above, the material to be rolled A is rolled caliber, finally finish A5 is shaped in the rolling described with reference to FIGS. 2-6. [0043] 　The configuration of the first grooved to fifth hole type have been described above in the present embodiment are illustrative, not limited to the embodiment shown, for example, grooved arrangement order and each rolling mill can be appropriately changed according to the arrangement grooved shape, various caliber modifications grooved conditions such as plant condition and product size for increasing or decreasing sequence of the. In addition, depending on the type of material, it is also conceivable to provide a caliber such preformed grooved used for rough shaping process from the material separately. [0044] 　According to the studies of the present inventors, in the intermediate rolling process according to the caliber 59 and caliber 69 in the manufacturing process, the rolling is performed while maintaining the balance of stretching the web corresponding section 3 and the flange corresponding 5,6 even if, as shown in FIGS. 3 and 4, since the roll diameter of up and down by the upper and lower grooved roll different sites, the relative sliding speed between the material to be rolled a (in particular a flange corresponding portion 5, 6) roll site by different. In the flange corresponding portion 5,6, a site having a large difference of the upper and lower roll diameter elongation of the rolled material is suppressed by the peripheral speed difference between the upper and lower rolls, whereas, the position corresponding to the diameter of the upper and lower rolls are equal pitch line (hereinafter , and is easy to cause elongation in to) as "neutral line", longitudinally compressive stress neutral line near the flange of the roll bite outlet is liable to occur, if the compressive stress exceeds the buckling limit, the flange corresponding portion the 5,6 shape defect occurs so-called flange wave. [0045] 　In particular, in the manufacture of large steel sheet pile as large hat-shaped steel sheet pile flange width / flange thickness ratio of elongation of the neutral line near the flange tends to increase relatively with respect to the elongation of the web, the flange corresponding portion 5 longitudinal compressive stress acts from the roll bite in the center of the 6. Moreover, since drops buckling limit stress, as a result, the flange wave is remarkably apt to occur. 　If the same caliber is rolling in one pass, by designing the shape of the grooved Considering flange stretching and web stretching by the relationship with the immediately preceding grooved shape, it is possible to suppress the flange wave. However, when performing rolling or two passes of the same caliber, because the rolling of the second pass after the stretching of the web corresponding section and a flange corresponding portion and the arm corresponding portion is defined by the shape of the grooved, conventional It is designed hole-like shape as it is not possible to suppress the occurrence of flange wave in the middle reverse rolling was found. For example, if the reverse rolling is performed in these holes type 59 and 69, the flange corresponding portion 5,6, meat gathered in the central portion of the flange corresponding 5,6 (neutral line near) each time rolling, the flange thickness phenomena such as the restoration that is likely to occur revealed the results of the investigation. When restoration of thickness occurs, would flange stretching in the next pass is increased, undesirably more easily flange wave occurs. [0046] 　Furthermore, when comparing the caliber 59 and caliber 69, since the direction of the caliber 69 which is downstream of the hole-type rolling thin more the material to be rolled A (in particular a flange corresponding portion 5, 6), the flange waves described above shape easy to bad becomes significant such occurrence. Further, it steps closer to the finish rolling, the shape defect occurs, it is easy to direct the product shape defect. That is, from the viewpoint product dimensional accuracy and rolling stability, it is important in particular solving the above problems in the caliber 69 is a hole type in the subsequent stage. [0047] 　In view of such problems, the present inventors have conducted extensive studies on the shape of the grooved 59 and 69 described with reference to FIGS. 3 and 4, given as a shape defect called the flange wave does not occur led to inventing a hole shape that satisfies the conditions. Hereinafter, undergo further improvements to the shape of the hole type 69, the detailed shape of such flanges wave does not occur structure as the grooved 69 'will be described with reference to the accompanying drawings. In the following is shown, be described by way of particular rolling shaping of the flange corresponding portion 6 of the caliber 69 'as an example, the caliber of interest in the present invention performs the thickness reduction for the entire material to be rolled A a grooved, but is not limited to the caliber 59 and 69. [0048] 　Figure 7 is a schematic illustration of the third grooved 69 configuration grooved an improved 69 'shows a schematic overall view (a), the portion facing the flange corresponding portion 6 (b) shows an enlarged view of the vicinity (a portion surrounded by a broken line in FIG. 7 (a)). Here, FIG. 7 (b) shows a state after the rolling in the caliber 69 'illustrates the material to be rolled A which is rolled by a dashed line. In FIG. 7, shown with the same reference numerals for the components having the same function configuration as the caliber 69 described with reference to FIG 4, the description thereof is omitted. [0049] 　In an improved grooved 69 'shown in FIG. 7, the opposing portion 100 opposed to the flange corresponding portion 6 of the rolled material A is different from the grooved 69 and shape, specifically, close to the web side in order from, different flange facing portion 100a of the tilting, 100b, and a 100c. These flanges opposing portions 100a, 100b, relates 100c, in this specification, "first flange facing portion" a flange facing portion 100b, a flange facing portion 100a disposed on both sides thereof, the 100c "second flange facing portion", defined as "third flange facing portion", sometimes referred to. Also, site "first flange portion" of the flange corresponding portion 6 which is rolled shaped by a flange facing portion 100b positioned in the center, each portion (flange portion facing 100a of the flange corresponding portion 6 arranged on both sides thereof, by 100c site) to be rolled shaped "second flange portion", defined as "third flange", sometimes referred to. 　Incidentally, as shown in FIG. 7 (a), it is configured for the portion 101 facing the flange corresponding portion 5 of the rolled material A likewise flange facing portion 101a, 101b, from 101c. [0050] 　Flange facing portion 100a, 100b, respectively inclination angle with respect to the horizontal line 100c θf2, θf1, a θf3, θf1 has a greater angle than Shitaefu2 and Shitaefu3. Further, Shitaefu2 and θf3 may at equal angles. Flange facing portion 100a, 100b, spacing of the upper grooved roll 65 and the lower grooved roll 68 in 100c tf2, tf1, tf3 (also called roll gap) is constant in each (upper grooved roll 65 and the lower grooved roll 68 flange facing portion 100a, 100b, if 100c of parallel) of the angle at each of the upper grooved roll 65 and the lower grooved roll 68 θf2, θf1, θf3 are equal. On the other hand, the flange portion facing 100a, 100b, when the angle between 100c and the horizontal line different on grooved rolls 65 and the lower grooved roll 68, the angle θf2, θf1, θf3 the upper grooved roll 65 and the lower grooved roll 68 it may be the average value of the angle between the flange facing portion and the horizontal line. Further, the inclined angle θf2, θf1, θf3 can be defined by the angle between the center line S and the horizontal line in the roll gap of the upper and lower grooved roll are substantially the same. 　The flange opposing portions 100b is configured to position astride the neutral line O in the height direction, the flange facing portion 100a is positioned closer to the web than its flange facing portion 100b, close to the arm (joint) flange facing portion 100c on the side are located. That is, the flange facing portion 100b is positioned so as to straddle the neutral line O, is configured to position the flange portion facing 100a, 100c are on both sides. [0051] 　Here, the stretching of the per pass was defined as the ratio of thickness before rolling to the thickness after rolling (after 1 pass), the thickness caliber 69 'represent a plate thickness direction of the roll gap in, the caliber 69' If the Δg roll gap reduction ratio in the vertical direction of a path in the reverse rolling in, the flange facing portion 100b, 100a, per one pass of 100c stretching λf1, λf2, λf3 the following formula (1) - (3 ) represented by. 　= Tf'1 Ramudaefu1 / Tf1 = (Tf1 Tasu Derutag · Cosshitaefu1) / Tf1 · · · (1) 　Ramudaefu2 = Tf'2 / Tf2 = (Tf2 Tasu Derutag · Cosshitaefu2) / Tf2 · · · (2) 　Ramudaefu3 = Tf'3 / Tf3 = (tf3 + Δg · cosθf3) / tf3 ··· (3) in addition, tf'1, tf'2, the Tf'3, flange corresponding portion corresponding to the respective flanges opposing portions 100b, 100a, 100c in the grooved 69 ' 6 is a roll gap corresponding to the thickness before rolling. Further, tf1, tf2, and tf3 are the flanges facing portion 100b, 100a, roll gap corresponding to the thickness of the flange corresponding portion 6 which is rolled in each 100c in caliber 69 '. 　In other words, by the tf1, tf2, θf1 the θf2 and greater angle than θf3 based on the relationship tf3, in rolling at the caliber 69 ', the following equation (4), are satisfied (5). 　Ramudaefu1 θf2, because to form a steep slope portion to be θf1> θf3, λf1 <λf2, λf1 web stretching lambda] w, equation (6) described in the above embodiments since a rolling shaping that does not satisfy, the occurrence of the flange wave was confirmed. 　Further, under the condition 7 (Comparative Example), and a flange thickness of a product thicker 1.2 mm, the value of λf1 / λw to satisfy equation (6) has performed a rolling under the conditions of 0.995, condition 6 for performing the rolling shaping without forming a steep portion in the grooved like the generation of flanges wave was confirmed. 　That is, in the comparative example of conditions 6 and 7, without forming a steep slope portion to the caliber, for performing the rolling shaping under conditions such that a constant at any position the inclination angle of the flange portion, the position of the flange portion ( Unlike stretching depending on the site), flange wave has occurred. 　From the above, it is suppressing inhibition of flanges waves by bending the flange portion facing the grooved into three parts, it can be seen that the flange thickness becomes possible thin size of the production. Industrial Applicability [0080] 　The present invention is applicable for example hat-shaped steel sheet pile, the manufacturing technology of the steel sheet pile having a flange, such as U-shaped steel sheet piles. DESCRIPTION OF SYMBOLS [0081] 　　1 ... rolling equipment 　　3 ... web corresponding section 　　5,6 ... flange corresponding portion 　　8,9 ... arm corresponding section 　　10, 11 ... joint corresponding section 　　14, 15 ... claw portion 　　17 ... roughing mill 　　18 ... first intermediate mill 　　19 ... the second intermediate mill 　　30 ... finishing mill 　　45 ... (first hole type) upper grooved roll 　　48 ... (first grooved) lower grooved roll 　　49 ... first caliber 　　55 ... (second the grooved) upper grooved roll 　　58 ... (second grooved) lower grooved roll 　　59 ... second hole type 　　65 ... (third grooved) upper grooved roll 　　68 ... (the third hole-type) lower grooved roll 　　69 ... third grooved 　　third grooved is 69 '... improvements 　　75 ... (first four grooved) upper grooved roll 　　78 ... (fourth grooved) lower grooved roll 　　79 ... fourth grooved 　　85 ... (fifth hole type) upper grooved roll 　　88 ... (the fifth grooved) lower grooved roll 　　89 ... fifth grooved 　　100 ... facing portion 　　100a ~ 100c ... flange facing portion 　　101a ~ 101c ... flange facing portion 　　A (A1 ~ A5) ... the rolled material 　　L ... rolling line 　　O ... neutral line The scope of the claims [Requested item 1]The grooved rolling a manufacturing method of forming a steel sheet pile having a flange from the rolled material, wherein the same caliber comprising a step of performing reverse rolling against the material to be rolled, performs the reverse rolling process includes the step of forming a first flange portion which straddles the neutral line, the second and third flange portions disposed on both sides of the first flange portion, 　the hole type, forming the first flange portion includes a first flange facing portion for a second flange opposing portion to form a second flange portion, and a third flange face portion to form a third flange portion, with respect to the horizontal plane, the inclination angle of the first flange facing portion being larger than the inclination angle of the second and third flange facing portion, the method of manufacturing a steel sheet pile having a flange. [Requested item 2] Step of performing the reverse rolling, and the web handling section includes the step of forming the arm corresponding portion, the hole type, and the web face portion to form a web handling unit, for forming the arm corresponding portion of the arm facing portion comprises, the caliber, the the web-side flange facing subgroup the second flange facing portion comprising at least one, said third flange facing portion at least one comprising an arm side flange facing subgroup When provided with, a boundary portion between the said web-side flange facing subgroup web facing portion, with respect to a straight line connecting the boundary portion between the arm-side flange portion facing unit and the arm opposed portion, the second flange facing portion is convex toward the flange outwardly, the third flange facing portion, characterized in that the flange inwardly a convex shape, the steel sheet pile having a flange according to claim 1 Production method. [Requested item 3] In the grooved flange stretching λf1 in the first flange portion, the flange extending λf2 in the second flange portion and the third flange portion, wherein the smaller rolling than λf3 is performed, according to claim 1 or the method of manufacturing a steel sheet pile having a flange according to 2. [Requested item 4] Said first flange portion, a second flange portion, and forming a third flange portion, characterized in that an intermediate rolling step, a flange according to any one of claims 1 to 3 method of manufacturing a steel sheet pile. [Requested item 5] The caliber is characterized by having a hole shape that both end portions are opened in the width direction, a method of manufacturing a steel sheet pile having a flange according to claim 4. [Requested item 6] It said first flange portion, a second flange portion, and a flange corresponding portion of the bent shape formed on the rolled material by the step of forming the third flange section, the desired flatness by rolling in the subsequent caliber of the process characterized in that it is rolled shaped into shape, manufacturing method of a steel sheet pile having a flange according to any one of claims 1 to 5. [Requested item 7] In the hole-type, the flange stretching λf1 in the first flange portion, characterized in that the rolling is carried out such that the following web stretching lambda] w, a flange according to any one of claims 1 to 6, method of manufacturing a steel sheet pile with. [Requested item 8] Characterized in that the steel sheet pile is hat-shaped steel sheet pile, a manufacturing method of a steel sheet pile having a flange according to any one of claims 1 to 7. [Requested item 9] A production facility for forming a sheet pile having a flange from the rolled material by grooved rolling, the comprises a rolling mill to perform a reverse rolling against the rolled material of the same caliber, performs the reverse rolling mill includes a first flange portion which straddles the neutral line, the caliber of forming the second and third flange portions disposed on both sides of the first flange portion, the hole type, the first flange portion It includes a first flange facing portion for forming a second flange opposing portion to form a second flange portion, and a third flange face portion to form a third flange portion, the horizontal plane for the inclination angle of the first flange facing portion may be greater than the inclination angle of the second and third flange facing portion, manufacturing facility of steel sheet pile having a flange. [Requested item 10] Rolling mill to perform the reverse rolling, a web-enabled unit includes a grooved to form the arm corresponding portion, forming the hole type, and the web face portion to form a web handling section, the arm corresponding portion and a arm portion opposed to, the caliber, the second flange facing portion at least one comprising a web flange facing subgroup, the third flange facing portion of the arm-side flange facing comprising at least one comprises a subgroup, and a boundary portion between said web-side flange facing subgroup and said web opposing portions, relative to a straight line connecting the boundary portion between the arm-side flange portion facing unit and the arm opposed portion, wherein second flange facing portion is convex toward the flange outwardly, the third flange facing portion, characterized in that the flange inwardly a convex shape, the steel sheet pile having a flange according to claim 9 Manufacturing facilities. [Requested item 11] In the grooved flange stretching λf1 in the first flange portion, the flange extending λf2 in the second flange portion and the third flange section, and wherein the less than Ramudaefu3, according to claim 9 or 10 manufacturing facility of steel sheet pile having a flange. [Requested item 12] The hole type, characterized in that it is a hole type provided in an intermediate rolling mill, manufacturing equipment of steel sheet pile having a flange according to any one of claims 9-11. [Requested item 13] The caliber is characterized by having a hole shape that both end portions are opened in the width direction, manufacturing facility of steel sheet pile having a flange according to claim 12. [Requested item 14] It said first flange portion, a second flange portion, and, subsequent holes rolling shaping a flange corresponding portion of the bent shape formed on the rolled material by rolling in the caliber of forming the third flange portion to the desired flat shape characterized in that it comprises a mold, manufacturing facility of steel sheet pile having a flange according to any one of claims 9-13. [Requested item 15] In the hole-type, the flange stretching λf1 in the first flange portion, and equal to or less than the web stretching lambda] w, manufacturing facility of steel sheet pile having a flange according to any one of claims 9-14 . [Requested item 16] Characterized in that the steel sheet pile is hat-shaped steel sheet pile, manufacturing facility of steel sheet pile having a flange according to any one of claims 9-15.