An X-ray apparatus capable of performing both computerized tomography (CT) imaging and usual radiography imaging (usual imaging) can realize high definition even in the usual imaging. In the X-ray apparatus, for the usual imaging, since a chair serving as a supporting structure for supporting a subject on a rotatable table is not required, the chair is withdrawn from an imaging field. The usual imaging is controlled so as to be permitted when the supporting structure is withdrawn from the imaging field. For imaging a knee, for example, sliding the chair allows imaging keeping the knee being in the rotation center. Therefore, a wide variety of imaging operations can be realized with a single flat-panel sensor.