Black pixels of image signals are expanded (122), a plurality of black pixel regions obtained by expanding the black pixels are connected to each other (123), and the circumscribing rectangles of the connected regions are extracted (124). In accordance with characteristics of the positions and sizes of the extracted circumscribing rectangles and the direction of characters in the circumscribing rectangles, whether the direction of the image is longitudinal or lateral and whether the image faces upwards or downwards are determined (126). In accordance with a result of the determination, configuration of the plural original document images on a sheet is decided (162). The plural original documents are combined into one composite image with the decided configuration (163). Therefore, a required copy output can be obtained regardless of the direction of the original document employed by a user and the direction of the original document set by the same.