To provide a circuit breaker formed so that the resin piece, sandwiched between a screw head and a screwing counter part in a state that metal parts are screwed sandwiching the resin piece, can be easily removed when disjoining the circuit breaker by a crusher and separating reusable material.

A groove for crushing 11a is formed to the back surface of a base 11 by making a screw insertion hole, fixing a jointing arm part by a screw, communicate with an adjacent screw insertion hole through a screw insertion hole of the base 11, and the concave part of the groove for crushing 11a is extended to a bearing surface 11b to which, the screw head is touching.