Abstract: In a circuit breaker utilizing a toggle link mechanism, the reset operation is facilitated. A block link including a reset pin, a first hole and a second hole is provided. The reset pin is inserted into a circular arc shape third hole formed concentric with the rotation of a trip lever formed at a secured frame. An actuating pin of a handle lever is inserted into the first hole. A shaft provided at a movable contact holder is inserted into the second hole. By this mechanism, the friction in the reset operation can be reduced to allow the reset operation to be perform by a smaller force. As a result, an auxiliary handle is not required. The handle and electrical operation devices can be reduced in size. Also, the operating handle is prevented from moving to the OFF position when the switching contacts are welded.