To shut off an electric path, even if a retention member for retaining a deformation member for opening and closing the electric path is separated.

A circuit breaker 90 includes the electric path formed from a terminal 94a to a terminal 94b through a rivet 96a, a first conductive member 98a, a third conductive member 98c, a cap 112, a second conductive member 98b, and a rivet 96b. In the electric path formed in the circuit breaker 90, a switching part 100 and the cap 112 are connected in series. Since the cap 112 makes up the electric path by being connected in series with the switching part 100, when the cap 112 is separated from a circuit breaker body 92, an electric path connecting a third conductive member 98c and the second conductive member 98b is shut off to break the path from the terminal 94a to the terminal 94b.