An indoor unit of an air-conditioning apparatus, comprising:
a main body provided with an opening port; and
a rectangular decorative panel attached to the main body to cover the opening port, the decorative panel including a rectangular suction grille provided to face the opening port of the main body, the suction grille having one side rotatably supported on one side of the decorative panel, and being detachably attached to the decorative panel,
the one side of the suction grille and the one side of the decorative panel being secured to each other by a plurality of fall prevention strings each extending between the suction grille and the decorative panel,
the decorative panel being provided with two panel claw portions to which respective portions of the plurality of fall prevention strings are to be hooked,
the suction grille is provided with two grille claw portions to which respective end portions of the plurality of fall prevention strings are to be hooked, and
the two panel claw portions and the two grille claw portions being arranged such that a distance W1 between the two panel claw portions is greater than a distance W2 between the two grille claw portions. [Claim 2]
The indoor unit of claim 1, wherein
the two panel claw portions are arranged in a longitudinal direction of the decorative panel, and the two grille claw portions are arranged in a longitudinal direction of the suction grille, and
the distance W1 between the two panel claw portions and the distance W2 between the two grille claw portions are determined such that tension forces X by the fall prevention strings which act in the longitudinal direction of the suction grille are equivalent to tension forces Z by the fall prevention strings which act in a vertical direction. [Claim 3]

The indoor unit of claim 2, wherein
each of the fall prevention strings is extended and inclined at an angle of 45 degrees with respect to the longitudinal direction of the suction grille 12. [Claim 4]
The indoor unit of any one of claims 1 to 3, wherein
the suction grille includes long-side wall portions facing to each other,
each of the two grille claw portions includes:
an intermediate wall portion having a plate-like shape and protruding from the long-side side wall portion in a width direction of the suction grille; and
a protrusion portion having a semi-annular shape and ends connected to the intermediate wall portion, and
the protrusion portions of the two grille claw portions are formed to protrude from surfaces of the intermediate wall portions of the two grille claw portions, the surfaces of the intermediate wall portions of the two grille claw portions being located on opposite sides of sides of the intermediate wall portions which face each other. [Claim 5]
The indoor unit of any one of claims 1 to 4, wherein
the decorative panel includes:
a center frame portion which is located at a center of the decorative panel in the width direction as seen in plan view, and extends in the longitudinal direction; and an outer frame portion which is located at an end portion of the decorative panel in the width direction as seen in plan view, and which faces the center frame portion and extends in the longitudinal direction, and
each of the panel claw portions includes:
a pillar portion formed to protrude from an inner wall portion forming a surface of the outer frame portion which faces the center frame portion, the pillar portion having ends one of which is connected to the inner wall portion and an other end of which is bifurcated into two end portions; and
curved portions curved from the end portions of the pillar portion toward a connection portion between the inner wall portion and the pillar portion, the curved

portions forming distal end portions of the panel claw portion. [Claim 6]
An air-conditioning apparatus provided with the indoor unit of any one of claims 1 to 5.