A gas insulated switchgear includes: an enclosure; a stationary contact arm fixedly installed within the enclosure; a movable contact arm installed to be moved within the enclosure such that it is brought into contact with or separated from the stationary contact arm; a cam reciprocating between closing and opening positions to move the movable contact arm; and an actuator moving the cam, wherein the cam includes first and second cam surfaces, and when the cam moves to an opening position by the actuator, movement acceleration of the movable contact arm by the first cam surface is greater than movement acceleration by the second cam surface and a movement distance of the movable contact arm by the first cam surface is smaller than a movement distance by the second cam surface.