A circuit breaker of different interruption speeds, and a spring operation mechanism is standardized for designing and manufacturing the circuit breaker. The circuit breaker has a power transmission mechanism for driving a movable contact 63 and a fixed contact 64 and an interruption spring 26 that imparts a driving force to separate the contacts through the power transmission mechanism. A latch mechanism restricts movement of the power transmission mechanism, and a pull-out operation section releases the restriction of the power transmission mechanism by the latch mechanism. The pull-out operation section is arranged to oppose a first arm of a lever to rotate the first arm. The lever is arranged so that a tip of a second arm is able to engage with and rest on the latch mechanism, and release the restriction of the power transmission mechanism by the latch mechanism.