To prevent a fixed contact point and a movable contact point from being shifted and obtain a structure without assembling through complicated caulking.

Plural positioning protrusions 28 are formed on a base plate 2, and a supporting point protrusion 21 for supporting a mounting shaft 24 horizontally is formed so as to be erected. Positioning holes 35 and 44 are formed at a flexible printed wiring board 3 and a flexible sheet 4, and positioning thereof by a positioning protrusion 28 is performed. Shifting of a fixed contact point 33 of the flexible printed wiring board 3 and of a movable contact point 43 of the flexible sheet 4 can be prevented. A key top 5 is fitted to the mounting shaft 24, the flexible printed wiring board 3 and the flexible sheet 4 are assembled into the base plate 2 by means of the key top 5, and assembling through caulking is made unnecessary.