A circuit breaker is provided to prevent a handle shutter from being inserted into the inside of an apparatus by restricting a movement range of the handle shutter by a stopper installed at the side of a cover. A circuit breaker includes breaker components including an operation handle(7) mounted on a main body case composed of a case and a cover(3). A handle unit penetrates a handle window frame(2B-1) opened on the cover and protrudes to the outside. A sheet-shaped handle shutter(10) is laid on a top surface of a base by loosely fitting in the handle unit of the handle as a closing member for closing a gap between a base of the operation handle and the handle window frame. The handle shutter extends from a front edge of the base positioned on the handle window frame to a front side and from a rear edge of the base to a front side respectively in ON and OFF positions of the operation handle to close the gap between the base and the handle window frame.
