To simplify the searching of an editing part on a preview screen.

A document shown by a display device 101 is edited and then displayed by a preview device 103 having resolution equivalent to the printing resolution to undergo the proofreading. If the document must be edited again in the proofreading process, an operator indicates the part to be edited aging on the screen of the device 103 by means of a coordinate input device 104. The position indicated by the operator is converted into a position in the document under editing by an information processor 203, and this converted position is shown by the device 101 as an editing position.