Aradiationtomographymethodof the present invention includes: calculating a radiating timing, with reference to imaging timing correction data relating a plurality of gantry angles to a plurality of imaging timing correction amounts, on the basis of an imaging timing at which a radiation source supported by a rotating traveling gantry is arranged at a predetermined imaging angle and an imaging timing correction amount, of the plurality of imaging timing correction amounts, related to a gantry angle at which the traveling gantry is arranged at the imaging timing； and calculating, on the basis of an X-ray image imaged with a radiation radiated from the radiation source at the radiating timing, three-dimensional data of the X-ray image of a subject. According to the radiation tomography method, the X-ray image imaged with the further accurately arranged radiation can be obtained even in a case where the traveling gantry deflects depending on the gantry angle at which the traveling gantry is arranged, and thus the three-dimensional data can be obtained more accurately.
