A push-button switch provided with a hollow push button (2), a case (3) supporting it, and a switching mechanism (6) having a first contact (41) disposed within the case (3) and a second contact (51) disposed opposite to the first contact (41), with one of its ends being inserted into a hole (2a) of the push button (2). Within a hole (61a) formed in an inserted section (61) of the switching mechanism (6), a slide block (8) is provided slidably in a direction crossing the direction in which the push button (2) is pushed. A slope (8a) capable of engaging with a slope (2b) of the hole (2a) of the push button (2) is formed on the slide block (8). A coil spring (return spring) (12) for energizing a shaft (62) of the switching mechanism (6) so as to abut the push button (2) is provided on the bottom (31) of the case (3). This configuration enables the push button (2) to take up a first OFF state, an ON state and a second OFF state in order of depression.