[Object] A compact gas-insulated switching apparatus in which the space for arranging a gas breaker module may be reduced, and the space for arranging a circuit wiring may be reduced in the vertical direction is proposed.[Means for Resolution] Gas circuit breakers for respective phases of a breaker module have the reference axial lengths having the same length between the first and second vertical planes and arranged so as to extend in the first direction, first circuit wirings for the respective phases of a first circuit wiring module are configured with gas-insulated buses respectively and are extended in parallel to each other along the second direction which is orthogonal to the first direction, the first circuit wirings for the respective phases are positioned at the respective apexes of a right angled isosceles triangle, the first circuit wirings respectively for the phase A and the phase B are positioned at both ends of the short side of the right angled isosceles triangle and are arranged on a third vertical plane positioned between the first vertical plane and the second vertical plane so as to extend in parallel thereto.