Circuit breaker

A circuit breaker comprises a shell, an operating mechanism and at least one circuit breaker pole, each circuit breaker pole comprises a pair of wiring terminals, a contact mechanism, an arc extinguishing system, a mutual inductor and a short circuit protection mechanism, and the operating mechanism, the contact mechanism and the arc extinguishing system are sequentially arranged in the first direction from an operating end to a wiring end. The wiring end is provided with at least one pair of wiring sockets arranged at intervals in the second direction, an air outlet communicated with the arc extinguishing system is arranged between each pair of wiring sockets, the mutual inductor, the contact mechanism and the short circuit protection mechanism are sequentially arranged in the shell in the second direction, and the first direction is perpendicular to the second direction. According to the invention, the gas outlet and the wiring socket are both arranged at the wiring end of the shell, so that the temperature