An image forming device configured as follows. A user is allowed to select desired print data files to be printed from among print data files stored in an external storage. A file list generating unit generates a list of the desired print data files selected by the user. The list includes an order of the desired print data files. A page arrangement unit arranges each page of the desired print data files on each recording sheet based on the list of the desired print data, a print mode and a total number of pages of the desired print data files. Blank pages to be added to complete the arrangement of pages of the print data files with respect to the recording sheets are generated. Page data is retrieved based on the arrangement of pages and is converted to image data, which is printed by an image data printing unit.