To improve usability when a user identifies and specifies a desired document from a plurality of documents stored in a memory without placing a burden on a device.

An image input/output device is provided with an input means for inputting a series of document data comprising a plurality of pages, an image output means for outputting the series of document data, and a storage means for recording/accumulating the series of document data. Image display data for the series of document data of the input/output device can be displayed on a display means, and a user can select whether to create the display image data for all pages of the series of document data to be processed.