It is an object to provide gas-insulated switchgear that occupies less installation space, in which the number of bellows to be used can be reduced, and that can minimize a work range in disassembling at addition or accident, and in reassembling. In double-bus gas-insulated switchgear in which a bus-side device is arranged above a breaker to reduce installation space to be occupied, a bellows is arranged between bus-side devices arranged vertically to each other, and under a support frame of the breaker, another support frame that can be separated therefrom is arranged, thereby enabling disassembling of a lower bus-side device alone.