Circuit breaker

The invention discloses a circuit breaker which comprises a direct current motor, a reduction gear box and a sliding block, and the direct current motor and the sliding block are both located below the reduction gear box. The sliding block is connected with the operating handle, the direct-current motor is connected with the input end of the reduction gearbox, the output end of the reduction gearbox is connected with the sliding block, and the direct-current motor drives the sliding block to slide after speed reduction of the reduction gearbox and drives the operating handle to achieve opening and closing of the circuit breaker. The accommodating space is located on one side of the operating handle to form a first mounting space, and the circuit board assembly comprises a first circuit board; circuit boards, except the first circuit board, of the circuit board assembly are arranged in the first mounting space, and the reduction gear box is arranged beside the first mounting space; the area of the upper surfac