An image processing apparatus which uses a tomogram group formed from a plurality of object tomograms or measurement data for generating the plurality of object tomograms, wherein the tomograms parallel to a plane containing first and second directions and aligned in a third direction different from the first and second directions, are provided. The image processing apparatus includes a storage unit which stores the tomogram group. The image processing apparatus specifies a plurality of tomograms from the tomogram group, and sets higher priorities for the specified tomograms or a predetermined number of tomograms adjacent to the specified tomograms than for other tomograms. The image processing apparatus reads out the tomogram group from the storage unit in descending order of the set priorities, and provides it to subsequent processing.
