An X-ray diagnostic apparatus includes a floor rotating arm (54) whose one end is mounted on a floor surface so as to be rotatable around a substantially vertical first rotation axis, a stand (53) which is mounted on the other end of the floor rotating arm so as to be rotatable around a substantially vertical second rotation axis, an arm holder (52) which is mounted on the stand so as to be rotatable around a substantially horizontal third rotation axis, a substantially C-shaped, C-arm (51) which is mounted on the arm holder so as to be slidable/rotatable around a substantially horizontal fourth rotation axis, with an isocenter at which the fourth rotation axis intersects the third rotation axis being located on the first rotation axis when the C-arm is folded above the floor rotating arm, an X-ray generating unit (1) mounted on one end of the C-arm, and an X-ray detecting unit (2) mounted on the other end of the C-arm.
