An X-ray imaging apparatus includes an X-ray generation part, an X-ray detection part, and a revolution drive mechanism. The X-ray generation part has an X-ray generator including a cathode and an anode, and emits an X-ray beam from the X-ray generator. The X-ray detection part detects the X-ray beam. The revolution drive mechanism performs X-ray imaging by revolving the X-ray generation part and the X-ray detection part around the object while the X-ray generation part and the X-ray detection part are opposed to each other with said object interposed therebetween. The X-ray imaging apparatus controls a restriction part to thereby restrict an X-ray transmission in such a manner that the focal spot size of an X-ray beam used in X-ray CT imaging of a relatively narrow imaging region is smaller than the focal spot size of an X-ray beam used in X-ray CT imaging of a relatively large imaging region.
