PURPOSE: To provide X-rays having a short rising time and little power consumption, reduce the ablation of a bearing portion due to heating, and reduce the maintenance work.

CONSTITUTION: Three-phase power is fed to three-phase coils 10 of a three-phase motor section 11 to rotate a target 1. A current from a filament electrode 4 is fed to a filament 5 for heating. When negative high voltage is applied to a cathode electrode 3 and positive high voltage is applied to an anode electrode, electrons emitted from the filament 5 are accelerated and collide with the focal point portion of the target 1 to generate X-rays. The X-rays are radiated from an X-ray radiation port 6.