In an X-ray imaging apparatus that performs X-ray CT imaging, an X-ray generator (13) that generates an X-ray cone beam (BX1) and an X-ray detector (21) that detects the X-ray cone beam (BX1) radiated to an object (specifically, image object (OB)) are revolved for 180 degrees to be opposed to each other with the object being located therebetween. Further, the X-ray generator (13) is moved such that a revolution reference point (CP) that is set on an optical path (CB) of the X-ray cone beam (BX1) goes round of a predetermined oval shape while the X-ray detector (13) and the X-ray generator (21) are revolved for 180 degrees. Setting is made such that a CT image area (CA) to be imaged by the irradiation of the X-ray cone beam (BX1) has an approximately triangular shape through the above-mentioned operation.