Circuit breaker

The circuit breaker comprises a moving contact assembly and further comprises a circuit board and a self-checking triggering mechanism, the self-checking triggering mechanism comprises a linkage piece and an elastic piece made of a conductive material, the circuit board is provided with a first conductive contact and a second conductive contact, and the elastic piece is provided with a first contact end and a second contact end. The first contact end is fixedly and electrically connected with the first conductive contact, the second contact end elastically abuts against the second conductive contact, the linkage piece is movably arranged and is in linkage with the moving contact assembly, and the moving contact assembly acts on the linkage piece to enable the linkage piece to push the second contact end to be separated from the second conductive contact when performing a closing stroke. The self-checking triggering mechanism can be automatically triggered once in the closing process of the circuit breaker, th