The present invention provides a breaker. The breaker comprises a pair of mutually cooperated moving contact and static contact, an arc extinguish chamber and an arc ignition runway facing the end protruding of the static contact and being divided into a first segment and a second segment through a protruding portion, wherein the free end of the first segment is close to the tail end of the moving contact, the free end of the second segment extends into the arc extinguish chamber, and the distance of the tail end of the static contact is smaller than the distance from any one point on the arc ignition runway to the tail end of the static contact. The breaker can allow the arc to rapidly depart from a contact area after formation and jump to the arc ignition runway so as to reduce the ablation of the arc to the contact; and moreover, the arc can be rapidly pushed to the arc extinguish chamber to effectively avoid the countermovement of the arc and the reigniting of the contact area.