In an image processing apparatus having an image reading unit 1 together with an image recording unit, an order sheet A having disposed thereon the thumb-nail image of an image capable of being record-outputted, and an order sheet B having disposed thereon a mark sheet section for designating image data corresponding to the thumb-nail image are record-outputted, the order sheet A and the order sheet B on which a user has effected marking are read by the image reading unit 1, the mark of a mark sheet section in the image on the read order sheet B is analyzed, and on the basis of the analysis, the assigned image data is record-outputted by the image recording unit. With the configuration, a reusable order sheet is provided to thereby enable the waste of resources and time to be saved, and efficient image processing to be carried out.