An image forming apparatus comprising: an image carrier including an intermediate transfer belt hung on a plurality of rollers including a backup roller and which carries toner image; and a transfer apparatus which transfers the toner image formed on the image carrier onto a recording sheet, wherein the transfer apparatus includes: an endless transfer belt; a plurality of rollers (702, 703) which stretches and supports the endless transfer belt and includes a press roller pressing the endless transfer belt against the intermediate transfer belt to the backup roller; an integrated pair of support side boards which rotatably support the plurality of rollers; a frame body of the transfer apparatus; a support member arranged at the frame body; a pair of press side boards, each of which is rotatably supported in a contacting and separating direction with respect to the image carrier by the support member arranged at the frame body of the transfer apparatus; a pair of swing sections (721, 723), each of which is arranged at each press side board, and supports the press side board, swingably with respect to the image carrier, while the endless transfer belt and the image carrier are pressed against each other; and a pair of urging members, each of which urges the press side board in a direction such that the press roller presses the endless transfer belt through the intermediate transfer belt to the backup roller. an image carrier including an intermediate transfer belt hung on a plurality of rollers including a backup roller and which carries toner image; and a transfer apparatus which transfers the toner image formed on the image carrier onto a recording sheet, wherein the transfer apparatus includes: an endless transfer belt; a plurality of rollers (702, 703) which stretches and supports the endless transfer belt and includes a press roller pressing the endless transfer belt against the intermediate transfer belt to the backup roller; an integrated pair of support side boards which rotatably support the plurality of rollers; a frame body of the transfer apparatus; a support member arranged at the frame body; a pair of press side boards, each of which is rotatably supported in a contacting and separating direction with respect to the image carrier by the support member arranged at the frame body of the transfer apparatus; a pair of swing sections (721, 723), each of which is arranged at each press side board, and supports the press side board, swingably with respect to the image carrier, while the endless transfer belt and the image carrier are pressed against each other; and a pair of urging members, each of which urges the press side board in a direction such that the press roller presses the endless transfer belt through the intermediate transfer belt to the backup roller. an endless transfer belt; a plurality of rollers (702, 703) which stretches and supports the endless transfer belt and includes a press roller pressing the endless transfer belt against the intermediate transfer belt to the backup roller; an integrated pair of support side boards which rotatably support the plurality of rollers; a frame body of the transfer apparatus; a support member arranged at the frame body; a pair of press side boards, each of which is rotatably supported in a contacting and separating direction with respect to the image carrier by the support member arranged at the frame body of the transfer apparatus; a pair of swing sections (721, 723), each of which is arranged at each press side board, and supports the press side board, swingably with respect to the image carrier, while the endless transfer belt and the image carrier are pressed against each other; and a pair of urging members, each of which urges the press side board in a direction such that the press roller presses the endless transfer belt through the intermediate transfer belt to the backup roller.