The present invention is intended to improve operability in page-by-page editing operation of a document file having multiple pages using a computer. A display processor displays multiple pages of the document file in list form on a display unit, selects an item to be displayed from a plurality of items contained in attribute information allocated to each page, and displays the attribute information relating to the item that has been selected in association with each page. An editing processor receives page selection operation and editing operation, executes editing process on a selected page, and updates the attribute information by rewriting an item associated with the editing process of the attribute information allocated to the selected page. After the editing process by the editing processor, the display processor selects an item to be displayed from the plurality of items of the attribute information based on the substance of the editing process to update a display item list of the attribute information.