The present application concerns a circuit breaker including a movable contact, a driving rod slidably mounted in the circuit breaker, a linkage mechanism for driving the movable contact, a pivoted driving fork rotatably mounted in the circuit breaker which cooperates with the driving rod through the cooperation of a primary pin provided on the driving rod and a primary slot provided on the driving fork, a driven lever connecting the driving fork to the movable contact, and wherein the driving rod supports a secondary pin which cooperates with a secondary slot of the driving fork when the driving rod in a position between a predetermined position and an extreme opened position of the circuit breaker.