A circuit breaker having a pair of spaced insulated stationary contacts engageable by a pair of movable contacts mounted to a conducting bridge on a movable contact arm is provided with common means defining main and auxiliary pivot axes for the contact arm. The main axis is transverse to the arm and provides a center about which the movable contacts pivot as they separate from the stationary contacts. The auxiliary axis is parallel to the longitudinal axis of the arm and provides a center for limited pivoting of the arm to obtain automatic seating of the movable contacts on the stationary contacts.