An embodiment includes an X-ray detecting section including an X-ray detector having a first visual field size and a high-resolution detector and having a second visual field size, an X-ray generating section for irradiating a subject with X-rays, an image processing section for generating a first X-ray image by means of the X-ray detector and a second X-ray image, a display section, a region defining section for displaying a spot corresponding to part of the second X-ray image or a region corresponding to the second X-ray image on the first X-ray image and specifying the position of the high-resolution detector by moving the spot or the region, a positional displacement calculating section for determining the coordinate difference between the center position of the first X-ray image and the position of the spot indicating the specified position and a move control section for controlling the top plate or the holding section.
