PURPOSE: To obtain a lightweight downsized gas insulated switchgear by embedding an intermediate ring between a shield ring embedded in an insulating spacer and a single phase high voltage conductor while surrounding the conductor.

CONSTITUTION: A single phase high voltage conductor 1 is supported by an insulating spacer 4 comprising a flange 2 and a mold 3 in an enclosure 6 filled with SF6 gas. A shield ring 7 for relaxing the electric field is connected with the flange 2 through a conductor 8 so that the electric field of the conductor 8 does concrete at an edge part of the flange 2. An intermediate ring 9 is disposed between the shield ring 7 and the conductor 1 while surrounding the conductor 1 and embedded in the mold 3 of the spacer 4. The intermediate ring 9 serves as an intermediate electrode between the conductor l and the earth through voltage division of a capacitor. The voltage between the intermediate electrode and the earth is measured by connecting a lead wire 11 insulated from the flange 2 through an insulator 10 and a lead wire 12 connected with the flange with an optical voltage sensor 13.