A push button switch has a structure in which a stem 15a of a key top 15 directly pushes a cup-shaped rubber 13, and a bulge 13b pushes a membrane switch 12a, and a first link member 16 in U form having a coupling portion 16e having a circular hole in the middle, and a second link member 17 are engaged with each other in an X-form to compose a link mechanism. Since the key top 15 directly pushes the cup-shaped rubber 13, if reduced in thickness, the motion stroke of the cup-shaped rubber 13 can be sufficiently maintained, so that the sensation of manipulation is excellent. When assembling the push button switch, the cup-shaped rubber 13 can be positioned and held in place by making use of the circular hole in the coupling portion 16e, and hence assembling is extremely easy.