The invention relates to a GIS. The GIS comprises: a GIS cylinder; a crank arm box fixedly connected to the GIS cylinder, wherein a moving contact seat is arranged at one end, close to the GIS cylinder, of the crank arm box; a moving contact assembled in the moving contact seat in a guiding manner; a crank arm arranged in the crank arm box, wherein the crank arm is in transmission connection withthe moving contact; a contact seat insulator arranged between the moving contact seat and the crank arm box, wherein the moving contact seat is connected to the crank arm box through the contact seatinsulator so as to form insulation with the crank arm box, the moving contact seat is provided with a protruding part, and the protruding part protrudes towards the GIS cylinder, the crank arm box isprovided with a grounding terminal, and a terminal insulator is arranged between the grounding terminal and the crank arm box, the grounding terminal is provided with an outer wiring end and an innerwiring end, the outer wiring end is located outside the connecting lever box and used for being connected with a grounding wire, the inner wiring end is located inside the crank arm box, and a switching conductor is arranged between the side, facing the crank arm, of the moving contact seat and the inner wiring end so as to achieve connection between the grounding terminal and the moving contact seat.