An X-ray diagnostic apparatus of an embodiment comprises a tabletop, an arm configured to support an X-ray tube and a detector such that the X-ray tube and the detector oppose to each other sandwiching a subject, a collimator configured to narrow an irradiation range of the X-ray, a detector moving equipment configured to cause the detector to make translational movement, and processing circuitry configured to control the collimator, and to accept information about an opening region of the collimator to acquire a movable range of the detector on a plane parallel to a detecting surface of the detector, and to cause, by the detector moving equipment, the detector to make translational movement relative to the X-ray tube within the acquired movable range.
