PURPOSE: To enable a rotary anode to be rotated without contact by radially and axially supporting it while allowing the magnetic flux of one permanent magnet to pass, through two sets of magnetic poles, into a cylinder which is made of a high permeability material and installed in the axial direction of the rotary anode.

CONSTITUTION: A cylinder 17 made of a high permeability material is installed in the axial direction of a rotary anode 3. Coils 33W36 which allow the magnetic flux of an annular permanent magnet 37, installed in the center of a yoke 25 placed outside a vacuum case 1 corresponding to the cylinder 17, to pass through a first and a second magnetic pole group 31a and 31b formed by horizontally dividing the yoke 25 so as to obtain magnetic attraction producing both radially supporting force and axially supporting force and which regulate the magnetic flux, are installed inside the cylinder 17. In addition, a driving motor 20 and displacement detectors 42 and 43 are installed, thereby constituting an X-ray tube device. As a result, the rotary anode 3 can be rotated without contact by magnetically supporting it axially and radially in a stable manner by use of one permanent magnet 37.