PURPOSE: To surely carry out the opening/closing operation of a switch cover without breaking a shaft and a shaft hole, even if the switch cover is turned rearward over necessity, by inwardly recessing the shaft of the switch cover.

CONSTITUTION: A switch cover 15 has a boss part 17' having a slide hole 16' at both side edges in the rear part. A shaft 18' is inserted into the slide hole 16', and a hook part 19' is formed at the lower edge, and a guide rib 20' is arranged at the upper edge. The hook part 19' is press-fitted into a square hole 21' formed at a part under the boss part 17', and each one edge of the shaft 18' is projectingly installed from the boss part 17', and axially supported in turnable manner in a shaft hole 13', and the other edge is urging-pressed in the projection direction by a spring 22'. The separatedly formed shaft 18' is put into free sliding by the spring 22', and the breakage of the shaft part can be prevented even if a shear load having a bending moment is applied on the shaft 18' in the case when the switch cover 15 is turned rearward over necessity, by inwardly recessing the shaft 18' inside the hole 16', without reducing the engagement portion between the shaft 18' and the shaft hole 13'.