An image forming apparatus includes an image carrier which moves while carrying an image and a transfer roller including a roller base material which faces the image carrier and rotates. A concave portion is positioned on a peripheral surface of the roller base material. A grip unit on the concave portion grips a recording medium. An elastic layer is disposed on a peripheral surface of the roller base material. The transfer roller grips a recording medium by the grip unit when the concave portion faces the image carrier and passes the recording medium through a nip between the image carrier and the elastic layer when facing each other so that the image carried on the image carrier is transferred on the recording medium. A roller driving unit rotates the roller base material. A control unit controls the roller driving unit to adjust a timing for forming the nip.