This invention realizes accurate positional offset correction between a plurality of tomograms captured by using a tomography apparatus. The invention is a tomography apparatus which corrects the positional offsets between a plurality of two-dimensional tomograms constituting a three-dimensional tomogram. This apparatus includes a tomogram analysis unit (120) which extracts feature amounts representing the tissue of a measurement target, a tomogram selection unit (140) which selects a standard two-dimensional tomogram from the plurality of two-dimensional tomograms based on the feature amounts, and a tomogram position correction unit (150) which calculates the positional offset amount between the nth two-dimensional tomogram adjacent to the standard two-dimensional tomogram and the (n−1)th two-dimensional tomogram.