In a circuit breaker, fixed electrodes 14 in pair are secured in a male housing 13. A female housing 21 which contains a moving electrode 30 is fitted into the male housing 13, whereupon the moving electrode 30 contacts and straddles the fixed electrodes 14 to make a short circuit. The moving electrode 30 comprises in integral combination retainer pieces 32 that are retained in an electrode retainer tube 22 in the female housing 21, a contact lug 31 that either contacts or detaches from the fixed electrodes 14, and a narrow-width joint 33 that joints the retainer pieces 32 and the contact lug 31 to make an integral unit. The narrow-width joint 33 flexes to deform, thereby absorbing the positional offset that develops when the contact lug 31 comes into engagement with the fixed electrodes 14.