The specification discloses an image forming apparatus which forms a visual image on a belt transfer member by at least one of image forming units and transfers the formed visual image onto a recording medium with the aid of the belt transfer member. In the image forming apparatus, the belt transfer member includes an endless belt wound on a plurality of tension rolls. A bending member, which bends the endless belt toward the inside of a tangential line connecting points on the outer circumferences of a couple of tension rolls, and locates the bent endless belt inside the tangential line, is additionally provided outside the endless belt located between at least the couple of adjacent tension rolls. An image forming unit may be additionally provided within an outside bending concave region of the endless belt, which is bent by the bending member and the tension rolls adjacent to the bending member.