A switch having a small thickness and constructed easily from a reduced number of parts comprises two complementary molded switch case members, each of which has fixed contacts with terminals integrally formed therewith and a common contact with a terminal integrally formed therewith. An operation member consisting of a disc portion and a stopper portion integrally formed therewith is provided between the case members and movable contacts having contact projections on their outer surfaces are secured to respective side surfaces of the disc portion of the operation member. A shaft member passes through the case members, the movable contacts and the operation member and is held in place with a fastener member. The upper portions of the case members are formed so as to define a slot therebetween which restricts rotary movement of the stopper portion projecting from the operation member.