An image forming apparatus determines the amount of cleaning toner that is supplied to each of an intermediate transfer belt 31 and a secondary transfer belt 42 based on the number of sheets that have been fed with the pick-up side of the sheet opposed to the intermediate transfer belt 31 and the number of sheets that have been fed with the pick-up side of the sheet opposed to the secondary transfer belt 42; integrally forms on the intermediate transfer belt 31 cleaning toner images that are supplied to each of the intermediate transfer belt 31 and the secondary transfer belt 42; and switches the application and the stop application of the transfer voltage for transferring the toner image from the intermediate transfer belt 31 to the secondary transfer roller 41 at a timing corresponding to the determined amount of toner.