To comprise a snap operation mechanism and switching mechanism with the fewer number of components.

The base end part of a fixed contact piece 10 and the base end part of a moving contact piece 20 are piled up through a spacer, fixed to a base with a screw 50, a U-shaped slit is formed in the base, and a cam 61 is fitted to the U-shaped slit so as to rotate between a first angle position and a second angle position. When the cam 61 exists in a first or second semi- fixing position, the cam 61 is pushed toward the outside of the rotating range with a moving contact piece tip part 21 (cylindrical curved part) interposed between the outer circumferential surface of the projection of the cam 61 and the inner surface of the U-shaped slit, and held in the semi-fixed position. When the cam 61 is rotated to the other semi-fixed position from one part, at first, the moving contact piece 20 is pushed to the fixed part side from the tip part by the projection part 64 of the cam 61, and the moving contact piece 20 is biased, then by the biasing force of the moving contact piece 20, the cam 61 is further quickly rotated, and stops in other semi-fixing position.