To extend the life of a bellows by setting cross-sectional curvature radiuses of valley portions and peak portions of the bellows to an optimum range, and equalizing a stress acting on the valley portions and peak portions during extension and contraction of the bellows.

In a vacuum valve, a main flow path 2 in which a valve seat 5 is opened and closed by a valve member 6 is separated from a driving part 10 for driving the valve member via a rod 7 by a bellows 8 disposed so as to surround the rod. The bellows 8 includes a number of valley portions 21 swelling inward of a metal pipe and peak portions 22 swelling outward of the metal pipe, and a ratio (valley R/peak R) of the cross-sectional curvature radius (valley R) of the valley portions to the cross-sectional curvature radius (peak R) of the peak portions is in the range of 1.15-1.70.