A circuit breaker, comprising a housing, wiring boards and terminals disposed within the housing, wherein: the terminal comprises a screw, a press board and a wire trap provided with a incoming line hole and a wiring space; the screw passes through a threaded hole on the top end face of the wire trap and contacts with the press board which is able to lift up and down and is embedded in the wire trap; the wiring board traverses the wire trap, and divides the wiring space of the wire trap into two independent wiring spaces (23, 24); a first wiring space is formed among the wiring board, the press board and the side walls of the wire trap, and a second wiring space is formed between the wiring board, the bottom end face of the wire trap and the side walls of the wire trap; a first line hole is provided on the housing at a position above the screw of the terminal; and the press board and the wire trap perform a relative displacement with the wiring board under the action of the screw to compress said two independent wiring spaces so as to realize the connection between wires; the circuit breaker being characterized in that further comprises a wiring bar annex configured to be connected to a bus bar wire; said wiring bar annex comprises a connecting bar connected to any one of the two independent wiring spaces (23, 24) and an insulation baffle used for fixing the connecting bar and provided with a incoming line hole; the insulation baffle is fixed on the housing; the connecting bar is provided with a wiring screw configured to be connected to a wire having an annular joint, and the housing is provided with a second line hole at a position above the wiring screw of the wiring bar annex. the terminal comprises a screw, a press board and a wire trap provided with a incoming line hole and a wiring space; the screw passes through a threaded hole on the top end face of the wire trap and contacts with the press board which is able to lift up and down and is embedded in the wire trap; the wiring board traverses the wire trap, and divides the wiring space of the wire trap into two independent wiring spaces (23, 24); a first wiring space is formed among the wiring board, the press board and the side walls of the wire trap, and a second wiring space is formed between the wiring board, the bottom end face of the wire trap and the side walls of the wire trap; a first line hole is provided on the housing at a position above the screw of the terminal; and the press board and the wire trap perform a relative displacement with the wiring board under the action of the screw to compress said two independent wiring spaces so as to realize the connection between wires; the circuit breaker being characterized in that further comprises a wiring bar annex configured to be connected to a bus bar wire; said wiring bar annex comprises a connecting bar connected to any one of the two independent wiring spaces (23, 24) and an insulation baffle used for fixing the connecting bar and provided with a incoming line hole; the insulation baffle is fixed on the housing; the connecting bar is provided with a wiring screw configured to be connected to a wire having an annular joint, and the housing is provided with a second line hole at a position above the wiring screw of the wiring bar annex.