A contact condition between a rotary electrode placed in a vacuum tank and a power supply mechanism for supplying power by being in contact with the rotary electrode is improved. A vacuum device comprising a vacuum tank, a rotary electrode placed in the vacuum tank in an electrically insulated state, and a power supply mechanism for supplying power by being in contact with the rotary electrode, wherein the rotary electrode has an annular shape, rotates horizontally relative to the central axis of the annular shape, the power supply mechanism has an electrode member, and the electrode member and the rotary electrode are in contact with each other at at least one contact surface.