An X-ray apparatus in this example of the invention includes a compression unit that enables to move independently of an X-ray tube supporting device and an X-ray detector for compressing a region of interest of a subject and a connecting part for connecting the X-ray detector to the compression unit and disconnecting the X-ray detector from the compression unit. Consequently, when the compression unit is not used, the compression unit is located in a retracted position. Thus a space can be secured around the subject placed on a top board. On the other hand, when the compression unit is used, the connecting part connects the X-ray detector to the compression unit. Thereby a compression member of the compression unit can always press a site of interest of the subject at the center of a detecting surface of the X-ray detector.
