To provide a tomograph and a tomographic method which suppress the occurrence of a pseudo image in a tomogram reconstituted based on projection data collected by photographing even when the whole of a subject juts from a visual field at all the photographic angle.

The tomograph is provided with: a storage part 23 which stores a CT image acquired previously by a separate apparatus of modality different from the tomograph; and a complementing part 25 which complements as imperfect projection data, imperfect real projection data collected by photographing in which the whole of the subject M is not included in the visual field of X-rays, by referring to the CT image. Thus, even when all the pieces of real projection data are the imperfect projection data, the real projection data can be complemented. Thus, a reconstitution part 27 can obtain the tomogram where the pseudo image caused by protrusion of the subject M from the visual field is suppressed.