Adjusting device and circuit breaker

The embodiment of the utility model provides an adjusting device and a circuit breaker, and relates to the field of circuit breakers. The adjusting device comprises a fixed part, a movable part and a limiting structure. The fixing piece is provided with a movable channel. The movable part is installed in the movable channel and connected with the fixed part. One end of the movable part abuts against the thermal release so as to adjust the initial position of the thermal release when the movable part moves along the movable channel. The limiting structure is arranged on the movable part and used for limiting the moving distance of the movable part in the direction close to or away from the thermal release. According to the embodiment of the invention, the movable part can move along the movable channel of the fixed part in the direction close to or away from the thermal release of the circuit breaker, and the limiting structure can limit the moving distance of the movable part together with the fixed part, so