An image data processing apparatus including: a compression processing section that divides image data into a plurality of partial data in a prescribed size, generates link information showing a mutual arrangement of each of the divided partial data, and generates compressed partial data by compressing each of the divided partial data; a plurality of expansion sections that expand the compressed partial data respectively; a data controller that assigns each of the compressed partial data to any one of the expansion sections, and operates the expansion sections to expand the compressed partial data substantially simultaneously; and an image data storage section that stores each of the expanded partial data, wherein the data controller determines an area of the image data storage section, in which each of the expanded partial data ought to be stored, and an output order of the stored partial data, based on the link information and the prescribed size of the partial data, so as to restore the original image data.