To provide an insulating spacer for gas-insulated electrical equipment which enables the downsizing of the insulating spacer and the simplification of the configuration.

A plurality of buried metal fittings 8 are provided on the virtual circumference of the periphery of an insulating spacer 1 which supports a high-voltage conductor by the center conductor 10 buried at the center. This buried metal fitting 8 is open to the side of a circular flange 4, and is shaped like a bottomed non-penetrated recess on opposite side, and an annular groove 7 for storage of a gasket is arranged outside the virtual circumference of arrangement of the buried metal fitting 8, and the insulating spacer 1 and the circular flange 4 are coupled with each other by a bolt 3 which is screwed into the thread part of the bottomed recess from the side of the circular flange 4.