A control knob is supported on a switch base via a first pivotal shaft. A movable contact holder holds a movable contact and is supported on the switch base via a second pivotal shaft substantially parallel with the first pivotal shaft. The movable contact holder is formed with first and second arms between which a sliding surface is formed. A control plunger sliding on the sliding surface is slidably fitted to the control knob. A return spring urges the control plunger in a direction to abut on the sliding surface. The control plunger is arranged such that, when the control knob tilts to the first and second operating positions, the tip end of the control plunger moves on the sliding surface to left and right sides with respect to a plane extending between axes of the first and second pivotal shafts, and such that the repulsive force of the return spring constantly urges the control knob toward the first operating position.