To provide a switch in which, by providing a self power-generation function in the switch itself, it can be utilized effectively as a power source of a failure forecast circuit or a forecast signal origination circuit.

An actuator member 6 which is operated in a reciprocating action by operation from the outside, a switch main body 1 which is switched by the reciprocating action of the actuator member 6, a magnetic member 16 and an induction coil 18 which are relatively displaced by the reciprocating displacement of the actuator member 6 are installed in a switch case 2, and the electric current induced by the induction coil 18 can be extracted.