To surely position a lighting block on a cover.

The cover 3 has a storage recessed portion 36 for storing the lighting block 8. In the storage recessed portion 36, approximately semi-columnar protruded portions 38, 38 are formed. The protruded portions 38, 38 are fitted to fitting recessed portions 84, 84 of a printed wiring board 81 to surely position the lighting block 8 on the cover 3 in the cross direction of the cover 3. Still, the protruded portions 38, 38 are fitted to the fitting recessed portions 84, 84 in the direction of storing the lighting block 8 in the storage recessed portion 36 (the longitudinal direction of the cover 3), therefore avoiding the worse assembling efficiency of the lighting block 8 on the cover 3.