1. An X-ray imaging apparatus for performing X-ray imaging, comprising: an X-ray generation part comprising an X-ray generation source including a cathode and an anode, a surface of the anode opposed to the cathode being formed as an inclined surface inclined with respect to a straight line connecting the anode and the cathode to each other, the inclined surface being formed by an X-ray generation surface which receives an electron beam from the cathode and generates an X-ray, the X-ray generation source generates an X-ray beam which is a flux of the X-ray generated by the X-ray generation surface toward a direction of reflection from the electron beam, the X-ray beam from the X-ray generation part being radiated toward an object; an X-ray detection part for detecting the X-ray beam emitted toward the object; a revolution drive mechanism for performing 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 the object interposed therebetween; an imaging mode selection section for selecting an imaging mode from a plurality of imaging modes having different ranges of radiation of the X-ray beam radiated to the object for X-ray imaging; and an emission control section for controlling the X-ray generation part in such a manner that an angle formed between the straight line connecting the cathode and the anode of the X-ray generation source and a central axis of the X-ray beam emitted from the X-ray generation part is increased in an imaging mode having a smaller range of radiation of the X-ray beam.