An image forming apparatus selects and combines necessary image sections from a plurality of documents thereby to obtain a combined image on one sheet of paper. The image forming apparatus is provided with an optical scanning system for exposing/scanning a document in relative movement therewith, a lever for setting a reference position to divide the document into a plurality of sections in the scanning direction of the document, a transfer belt for holding an image of each section at every exposure/scanning time, and a transfer charger for transferring the image held by the transfer belt to a paper, each of which is controlled so that the images of a plurality of the sections are combined and transferred at one time to the paper.