Form image management system and form image management method

A form image management system includes: a storage apparatus that stores a plurality of types of master images; and a computer that obtains a form image, that retrieves, from the storage apparatus, a master image having the highest correlation with the obtained form image from among the plurality of types of master images, that generates, as common-difference data, data of an image indicating a common-difference portion present in both a difference between the plurality of form images and a difference between the retrieved master image and one of the plurality of form images, that stores the common-difference data, that generates, in relation to each of the obtained form images, difference data relative to data which is the retrieved master image on which an image indicated by the common-difference data has been superimposed, and that stores the generated difference data in the storage apparatus.