PURPOSE: To improve the reliability of a device by constituting a fixed shaft for supporting a fixed side magnetic ring of a thrust load supporting magnetic bearing of a non-magnetic material.

CONSTITUTION: The fixed shaft 40 consists of a non-magnetic material and a single journal part 41 is formed on the slightly under side of the center part in the axial direction. Herringbone grooves 42 inclined in the rotating direction of a rotary assembly body 50 are engraved on the journal part with several μm depth in the direction from the upper and lower ends to the approximately center part. In addition, a fixed side magnetic ring 43 of the thrust load supporting magnetic bearing is externally fitted with a small diameter part formed on the lower side of the journal part 41 and fixed with a bonding agent or the like. Since the fixed shaft and the bearing part are constituted of the non-magnetic material, these parts are prevented from magnetization and attraction of a magnetic body. Thereby, the inflow of fine magnetic grains generated from the magnetic bearing or the like into a pressure air bearing is reduced and the rotary body can be precisely rotated.