A switch includes push knobs and a lens for guiding light from the light source on the pc board to illuminate the push knobs for changing the distance between the incident surface of the lens and the light source by moving the lens by operating the push knobs. The lens has a recess groove intersecting the light path of the incident light to the lens. The pc board has a protruding wall protruding toward the lens at a position corresponding to the recess groove. Upon movement of the lens directed to reduce the distance between the incident surface and the light source, the protruding wall is inserted into the recess groove by an amount corresponding to the lens displacement to shield the light path in accordance with the displacement. Light amount for illuminating the push knobs is kept constant irrespective of the lens movement.