[Claim 1] An elevator car, comprising:
a car compartment main body (100] having a floor panel (4], a side surface panel (6] erected on the floor panel (4], and a ceiling panel (5] installed above the side surface panel (6];
characterized by an installation piece (14] having a holding plate section (14b] held between an upper surface of the side surface panel (6] and a lower surface of the ceiling panel (5], an installation plate section (14e] extending from the holding plate section (14b] along a surface of the side surface panel (6] on the side of the car compartment main body (100], and a projection (14f] which projects from the installation plate section (14e] to the opposite side from the surface of the side surface panel (6] on the side of the car compartment main body (100]; and
an illumination device (12] having a projection groove (15c] into which the projection (14f] is inserted, the illumination device (12] being installed on the installation plate section (14e].
[Claim 2] The elevator car as claimed in claim 1, wherein the side surface panel (6] has a first coupling section (6b] in which a first coupling hole is formed; the ceiling panel (5] has a second coupling section (5c] in which a second coupling hole is formed;
the holding plate section (14b] is held between an upper surface of the first coupling section (6b] and a lower surface of the second coupling section (5c], and has a third coupling hole which coincides with the first coupling hole and the second coupling hole; and

the first coupling section (6b], the second coupling section (5c] and the holding plate section (14b] are coupled by a bolt (13a] passing through the first coupling hole, the second coupling hole and the third coupling hole.
[Claim 3] The elevator car as claimed in claim 1 or 2, wherein the illumination device (12] has a light-emitting device (16], and an illumination box (15] which houses the light-emitting device (16] and which is fixed to the installation plate section (14e] of the installation piece (14];
the illumination box (15] has a cable hole (15i] through which a power cable of the light-emitting device (16] is passed; and
a cable groove (23g] which connects the cable hole (15i] of the illumination box (15] and the outside of the car compartment main body (100] is formed in the installation plate section (14e] and the holding plate section (14b] of the installation piece (14].
[Claim 4] The elevator car as claimed in claim 3, wherein the light-emitting device (16] is fixed to a lower plate of the illumination box (15]; an upper surface of the illumination box (15] is open; and the cable hole (15i] is formed below the opening of the upper surface.
[Claim 5] The elevator car as claimed in claim 3, wherein the light-emitting device (16] is fixed to a lower plate of the illumination box (15]; an upper surface of the illumination box (15] is open; and the cable hole (15i] is formed below a light-emitting element of the light-emitting device (16].

[Claim 6] The elevator car as claimed in claim 1, wherein the side surface panel (6] has an upper surface section (14c] which extends to the outside of the car compartment main body (100] and which holds the holding plate section (14b], and a first edge section (6c] which extends downwards from the upper surface section (14c] on the outside of the car compartment main body (100];
the holding plate section (14b] of the installation piece (14] extends to the outside of the car compartment main body (100]; and
the installation piece (14] has a side surface section (14c] which extends downwards along the first edge section (6c] from the holding plate section (14b] on the outside of the car compartment main body (100], and a second edge section (14d] which extends from the side surface section (14c] to below the first edge section (6c].