A mechanical-puffer-type arc-extinguishing chamber includes a fixed main contact, a movable main contact that moves on an opening-and-closing axis in a connectable and disconnectable manner to and from the fixed main contact, and a mechanical puffer chamber that is provided in the movable main contact and blows compressed insulation gas to an arc. A thermal-puffer-type arc-extinguishing chamber includes a fixed contact, a movable contact that moves on the opening-and-closing axis in a connectable and disconnectable manner to and from the fixed contact, and a thermal puffer chamber in which compressed insulation gas is blown to the arc. The mechanical-puffer-type arc-extinguishing chamber and the thermal-puffer-type arc-extinguishing chamber are arranged in series on the opening-and-closing axis, and two breaking portions are electrically connected in series.