A rod (40) is pivotally provided in a lever (28). The rod (40) is divided into a small-diameter lower rod (37) and a large-diameter upper rod (38). When a knob (45) is pivotally moved, the lower rod (37) and the upper rod (38) are moved in an integrated fashion. A movable contact (31) is slid by means of movement of a pusher (57) of the lower rod (37). In this case, the rigidity of the upper rod (38) is improved, and hence the upper rod (38) becomes less susceptible to deflection induced by the load of the spring (53). Accordingly, inclination of the knob (45) toward the lever (28) is prevented, and hence a clearance between the lever (28) and the knob (45) can be maintained constant by means of a single set consisting of a spring (53) and a moderation ball (54).