To provide a moving contact body that hardly develops cracks even if a swelled part, or a base material swelled into one side is repeatedly depressed, and provides a longer service life, and also to provide a switch device using the moving contact body.

The contact body 1 used in the switch device 11 comprises the base material 2 made of a thin metal plate having elasticity, the swelled part 2a formed by reversibly swelling the center part of the base material 2, and a contact part 2b formed on the inner face of the swelled part 2a. The base material 2 has a pair of protrusions 2c, 2c, projecting outwardly by the width dimension G and the projecting dimension F from positions opposing each other on a circular outer peripheral. The protrusions 2c are formed with projecting dimensions F1 and F2, where F1 is the projecting dimension from the outer peripheral part at both ends 2d side in the width direction of the width dimension and F2 is the projecting dimension from the outer peripheral part at the center part in the width direction. The relation between F1 and F2 is assumed F1>F2.