PURPOSE: To provide a gas-insulated switchgear in which miniaturization of, and reduction in size of, the entire device is realized by contriving an arrangement between a lightning arrester and other devices.

CONSTITUTION: Single-phase bus lines 1 for three phases are made to branch off, in parallel, from a main bus 5, and a circuit breaker 4 is disposed on each single-phase bus line 1. A space is formed between a part of a covered conduit W on a breaker 4 side and a rising portion of the single-phase bus lines 1 bent like a letter U on the breaker 4 side. A lightning arrester 2 is disposed in this space. Specifically, the lightning arrester 2 is disposed below the single-phase bus line 1 in such a way as that the axis of the lightning arrester is in line with the axis of the single-phase bus line 1 when it is horizontally viewed. The lightning arrester 2 is arranged along the axis of each single-phase bus line 1, and does not project sidewards from the single phase bus line 1. Hence, the whole of a gas insulated switching device can be miniaturized and reduced in size by reducing an interval between the single-phase bus lines 1.