In order to provide an X-ray CT apparatus which reduces a waiting time period until irradiation with X-rays is permitted with a simple configuration without detecting a rotation speed of an anode, a controller (23) selects a rating anode rotation speed among a plurality of types thereof depending on an X-ray irradiation condition, and supplies driving power for realizing the selected rating anode rotation speed to a stator coil (81) from a starter circuit (10). The controller (23) obtains time required to reach an irradiation possible rotation speed which is lower than the rating anode rotation speed and is required to apply X-rays in an X-ray irradiation condition. If arrival time has elapsed, irradiation with X-rays is permitted. Consequently, it is possible to reduce a waiting time period in which an operator waits for an anode rotation speed to rise.
