To store an information-added document itself as a backup.

Information of a server and a file name are extracted by reading out the information-added document D5 embedded with information such as a document server 2 stored with an original electronic document and the file name by an image reading part 17 in a copying unit 3 (S1). A user selects the propriety of storage of an image in the document D5 (S3), and the user selects a holder in an external storage part 15 of the copying unit 3 when selecting the storage (S4). The image in the document D5 is read out (S5) to be stored in the holder in the external storage part 15 (S6). When finding the original electronic document based upon information on the extracted server and file name, the original electronic document is acquired from the document server 2 to be printed by the printing unit 3 (S8).