A print data processing apparatus performs combined printing of a plurality of pages including a page on which an image is oriented in a different direction from images on other pages. In the print data processing apparatus, the layout unit lays out, in a memory, print data of target pages in a number specified to be combined into a single print to create print data of a physical page and sends the print data to a printing apparatus to print the print data. The rotation-angle determining unit determines a rotation angle of an image on the target pages based on the specified number of the target pages, the paper feeding direction, the direction of an image on the first page of the target pages, the order in which the target pages are arranged, and the direction of an image on the target pages.