A first image enlargement processing section enlarges an original image to a specified size to generate an initial enlarged image. A domain block extraction section extracts a domain block image from the original image. A range block extraction section extracts a range block image from the neighborhood of the correspondence part of the domain block image in the initial enlarged image. A reduced range block preparation section reduces the range block image to the domain size to generate a reduced range block image. An enlarged range block preparation section enlarges the most similar range block image having the highest degree of similarity to an enlargement size to generate an enlarged pseudo domain block image. An enlarged image acquisition section 676 uses each enlarged pseudo domain block image to generate an enlarged image of the original image.