Circuit breaker

The utility model discloses a circuit breaker, which comprises a base, an upper cover, a moving contact and a rotating shaft, the moving contact is mounted on the rotating shaft and can rotate relative to the rotating shaft, and the circuit breaker is characterized in that the front end of the rotating shaft is provided with a first arc surface, and the position of the base matched with the rotating shaft is provided with a second arc surface; a gap used for blocking electric arcs is formed between the first arc surface and the second arc surface, and a groove is formed in the bottom of the second arc surface, so that the front-section gap is smaller than the rear-section gap. The rotating shaft is matched with the base and close to the arc extinguish chamber, the rotating shaft is matched with the base through arc surfaces, the gap is small, a large space is reserved in the rear part, and mechanism clamping stagnation caused by metal particles entering the gap between the rotating shaft and the base is avoid