A circuit interrupter consisting of a pair of contacts being relatively movable to be detachable in an arc extinct chamber filled with a fluid for arc extinction is disclosed. Also included are a chamber for storing the fluid pressurized in an arc space in which the arc is formed by the departing operation of the contacts and means for forming magnetic field in the arc space. The fluid for arc extinction is discharged from said chamber by opening a passage after departing the contacts for a specific distance and the arc is interrupted by puffing the fluid.