Abstract: A highly reliable gas circuit breaker capable of improving the braking performance and the insulating performance and a gas circuit breaker capable of allowing a stress acting on the supporting member of the electrode are provided. The gas circuit breaker comprising a grounded tank filled with an insulation medium; a movable electrode arranged inside the grounded tank; a fixed electrode which is supported through an insulator supporting member inside the grounded tank and disposed detachably from and oppositely to the movable electrode; and electric conductive parts individually provided in the movable electrode and the fixed electrode, wherein the insulator supporting member is a solid cone and supports the fixed electrode in an upper side of a central axis of the grounded tank.

Abstract: In order to provide a good gas-insulated circuit breaker which is compact and easy in assembling and preparation, a gas-insulated circuit breaker 100 is constructed with a grounded enclosure 104 enclosed a insulation nature gas, a current interruption part having a fixed contactor 115 arranged in the grounded enclosure 104 and a movable contactor 116 to be contacted with and to be separated from the fixed contactor 115, and an operating mechanism 101 to output a driving force to drive the movable contactor 116, wherein a grounded enclosure side main rotating shaft 110 connected to the movable contactor 116 through a connection member and a main output shaft 102 for outputting a rotating force to actuate the movable contactor 116 through the grounded enclosure side main rotating shaft 110 provided on the operating mechanism 101, are arranged on a coax so as to be coupled with a gear coupling 120, and the operating mechanism 101 is arranged almost under the grounded enclosure 104.