1 DESCRIPTION Title of invention SHAPED PRODUCT CONSTITUTED BY FIBER-REINFORCED COMPOSITE MAERIAL Technical Field The present invention reIates to a lightweight shaped product having degree of fieedom in shape, constituted by a fiber-reinforced composite material containing reinforcing fibers and a thermoplastic resin. The invention M e r relates to a shaped product preferably usable in housings for electric and electronic equipments, parts for automobiles, parts for medical equipments, parts for aircrafts, building materials and parts for general industries. The invention M e r relates to a method for manufacturing the shaped product in high productivity. Background Art In recent years, demand relating to weight lightening is increased in various fields such as electric and electronic equipments, automobiles, medical equipments, aircrafts, building materials and parts for general industries, and housing and members utilized therein have been required to lighten weight and have high rigidity A shaped product obtained by pressing a rolled plate of an aluminum alloy or a magnesium alloy, or a shaped product obtained by die-casting the same is used as such thin-walled and high rigidity housings and members. Furthermore, a shaped product obtained by injection-molding a fiber-reinforced composite material in which glass fibers or carbon fibers is filled therein, and a shape product obtained by integrating a fiber-reinforced composite material plate and a thermoplastic resin by injection molding have been used. The durninum alloy and magnesium alloy are excellent in strength and rigidity, but have a limit in, formability, and are therefore difficult to form a complicated shape in a single substance. Furthermore, a metaI member (particularly a magnesium alloy) has a problem that 2 corrosion resistance is poor. The surface of the metal member corrodes by moisture in the air or moisture and salt contained in sweat of a user, leading to occurrence of poor appearance. In view of this, Patent Document 1 proposes a method for producing a housing including a application step for applying the entire member constituted by a magnesium alloy with a resin layer and a molding step far integrally molding the member and a resin-made part. This method enables to form a complicated shape axxd to impart corrosion resistance. However, the steps become complicated, and additionally, specific strength of an aluminum alloy, a magnesium alloy and a resin is high relative to an iron, but is low as compared with a fiber-reinforced composite material described hereinafter. Therefore, there is a limit in achievable weight lightening. The fiber-reinforced composite material is excellent in specific strength and specific rigidity and furthermore excellent in corrosion resistance, and is therefore widely utilized in the above-described uses. Particularly, a shaped product obtained by injection molding a fiber-reinforced composite material in which glass fibers or carbon fibers is filled therein is widely used because of high degree of fieedom in shape and high productivity. However, because length of fibers remained in the shaped product is short, the problem still remains in the uses requiring high strength and rigidity. On the other hand, a fiber-reinforced composite material reinforced by a continuous fiber is particularly excellent in specific strength and specific rigidity, and therefore has been mainly used in the uses requiring high strength and rigidity. Elowever, the fiber-reinforced composite material has low degree of hedom in shape as compared with a resin and a fiber-reinforced composite material obtained by injection molding, and a complicated shape has been difficult to be fonned by a single substance. Furthermore, because the fiber-reinforced composite material is produced by layering a plurality of reinforcing fibers in a woven form, there has been a problem that productivity is low. Patent Document 2 proposes a combined shaped product in which a resin member is jointed to a plate-like member constituted by a sheet containing reinforcing fibers, particularly a continuous fiber, at an outer 3 edge of the plate-Iike member. This constitution enables to achieve a shaped product having a complicated shape. However, because the shaped product is produced through a plurality of steps, it is difficult to say that productivity is high. Furthermore, a fiber-reinforced composite material using a continuous fiber is generally obtained by heating and pressuring a material called a prepreg in which a base material of reinforcing fiber is previously impregnated with a thermosetting resin, for 2 hours or more by using an autoclave. In recent years, RTM molding method including setting a base material of reinforcing fiber in which a resin is not impregnated in a moId and then pouring a thermosetting resin in the mold is proposed, and a molding time has been greatly shortened. However, even in the case of using the RTN molding method, the time of 10 minutes or more is required to mold one part, and productivity is not improved. For this reason, a fiber-reinforced composite material using a themoplastic resin as a matrix has been focused in place of the conventional thennosetting resin. However, the thermoplastic resin generally has high viscosity as compared with a thermosetting 'resin. Therefore, there has been a problem that the time for impregnating a fiber base material with a resin is long, and as a result, takt time up to the molding becomes long. A technique called thermoplastic stamping molding (TP-SMC)h as been proposed as a technique to solve those problems. This technique is a molding method including heating chopped fibers previously impregnated with a thermoplastic resin to a melting point or a flowable temperature of the resin, or higher, introducing the chopped fibers in a pan of a mold, immediately closing the mold, and fluidizing the fibers and the resin in the mold, thereby obtaining a product shape, followed by cooling to form a shaped product. This technique enables the molding in a short period of time of about 1 minute by using fibers previously impregnated with a resin. Patent Documents 3 and 4 describe a method for producing chopped fiber bundles and molding materials, Those methods are methods using molding materials as called SMC or a stampable sheet. In such themoplastic stamping molding, the fibers and the resin are allowed to flow in the mold, so that there have been problems of failing to produce a 4 thin-walled one, and fiber orientation is disturbed, making it difficult to control. Patent Document 2 : JP-A-20 10-147376 Patent Document 2: JP-A-20 10- 13 1804 Patent Document 3: JP-A-2009- 1 146 1 1 Patent Document 4: JP-A-2009-1146 12 Disclosure of the Invention Problems that the hvention is to Solve The problem to be solved in the present invention is to provide a shaped product in high productivity, the shaped product being thin-walled and lightweight, having high rigidity and excellent surface appearance, and having a complicated three-dimensional shape. Means for Solving the Problems As a result of intensive investigations to solve the above problems, the present inventors have reached the present invention, That is, the present invention relates to a shaped product constituted by a fiber-reinforced composite material containing a discontinuous reinforcing fibers in a thermoplastic resin, wherein the reinforcing fibers contained in the shaped praduct has reinforcing fiber bundles (A) each constituted by the reinforcing fibers of the critical single fiber number or mare defined by the following formula (I), the ratio thereof to the total amount of the reinforcing fibers in the shaped product is 20 vol% or more and less than 90 voI%, and the average number (N) of the reinforcing fibers in the reinforcing fiber bundle (A) satisfies the folIowing formula (2): critical single fiber nmbe1=600/D (1) 4 2 0.7~10/ D2 < N