An image forming device for dividing a continuous document without the concept of pages, such as an HTML document, into pages, the device being capable of responding to a user's various needs in connection with page dividing. A page dividing processor (304) is provided with a plurality of page dividing algorithms which differ in terms of treatment of a document element placed across a page boundary. When a user inputs a page dividing policy using a user interface (301), a dividing algorithm designating section (305) specifies a page dividing algorithm corresponding to the policy, and notifies the page dividing processor (304) of the algorithm. The page dividing processor (304) divides an HTML document into pages according to the algorithm.