CIRCUIT BREAKER

PROBLEM TO BE SOLVED: To solve the problem that, when cutting off a DC small current of about 20 A in a circuit breaker, the cutoff is made difficult since a magnetic field generated between contacts is weak, it is difficult to drive an arc, and further there is no zero point like an alternating current.SOLUTION: A circuit breaker configured to cut off an overcurrent or a short-circuit current flowing to a cable run comprises: a stationary contact element connected to the cable run and including a fixed contact; a movable contact element including a movable contact contacted with or separated from the fixed contact; and an arc extinguishing device for extinguishing an arc generated between the contacts. The stationary contact element is formed by folding a power supply terminal to be inversely L-shaped, continuously folding it to be L-shaped, punching out a central part of a folded horizontal plate to be inversely U-shaped, and further folding the horizontal plate stepwise in the state where a central elongated protrusion remains. The fixed contact is disposed in the elongated protrusion of the stationary contact element, an arc runner is disposed on a rear side of the elongated protrusion, and a permanent magnet is installed in the arc runner.