An X-ray imaging apparatus operates by selecting an appropriate exposure sensitivity corresponding to the X-ray detector to be used. In the apparatus, an exposure sensitivity corresponding to the flat panel detectors used for an X-ray imaging is selected from multiple exposure sensitivities stored in an exposure sensitivity memory unit of the console, and the selected exposure sensitivity is displayed on the display unit of the high-voltage unit. An exposure control is executed based on the exposure sensitivity corresponding to the flat panel detectors used for the X-ray imaging, which is selected from multiple exposure sensitivities stored in an exposure sensitivity memory unit. The exposure control unit of the high-voltage unit suspends the X-ray irradiation from the X-ray tube when an integrated value of the X-ray detected by the X-ray dose sensor reaches to the setting-value set relative to the selected exposure sensitivity.
