A pair of fixed arc electrodes (30a), (30b) are arranged facing each other within a sealed container that is filled with arc-extinguishing gas 1. There are provided: a compression puffer chamber (12) for accumulating pressurized gas (35) that is obtained by elevating the pressure of the arc-extinguishing gas (1); and an insulated nozzle (32) that directs the pressurized gas (35) towards the arc discharge (7) from the compression puffer chamber (12). A buffer chamber (36) is provided, in which hot exhaust gas (20) generated by the heat of the arc discharge (7) is temporarily accumulated. A pressurized gas through-flow space (43) is provided, communicating with the compression puffer chamber (12) . In the pressurized gas through-flow space (43), an opening/closing section (41) prevents inflow of hot exhaust gas (20) by assuming a closed condition during the earlier half of the current interruption period, and in the latter half of the current interruption period the opening/closing section 41 is opened to allow flow of pressurized gas (35).