An image forming apparatus includes: a primary transfer section which transfers a toner image formed in an image forming section onto an intermediate transfer belt; a back-up roller arranged on an inner periphery side of the intermediate transfer belt; a secondary transfer roller that is in pressure contact with the back-up roller through the intermediate transfer belt and transfers the toner image from the intermediate transfer belt onto a transfer material while conveying the transfer material; a moving mechanism which moves a position where the secondary transfer roller is in contact with the back-up roller through the intermediate transfer belt; and a controller which controls the moving mechanism based on information relating to a thickness of the transfer material obtained by a thickness information obtaining section.