The image forming apparatus comprises an image reading device that reads a manuscript and generating a manuscript image data, and a command input device that inputs a command. A layout analysis device is provided for analyzing a layout of an image expressed by the manuscript image data. A controller is provided which, when a command is inputted trough the command input device, decides a page order for horizontally or vertically juxtaposed pages based on a result of analysis by the layout analysis device. An image splitting device generates split image data expressing two horizontally or vertically split images of the manuscript image data, and outputs the split image data in accordance with the order that is decided by the controller.