A transfer unit comprising: a belt member extended in a loop around a plurality of rollers and having a movable surface on which a toner image is transferred from an image carrier; a bending roller externally contacting the surface of the belt member to bend the belt member toward an interior of the loop and rotating in conjunction with movement of the surface of the belt member; a transfer section including one roller of the plurality of rollers and a rotatable surface moving member, the one roller located upstream from the bending roller and downstream from a transfer point at which the toner image is transferred from the image carrier onto the surface of the belt member in a surface moving direction of the belt member, the surface moving member facing the one roller of the plurality of rollers via the belt member, the transfer section transferring the toner image from the belt member onto a transfer material at a transfer nip formed as the surface moving member presses against the one roller via the belt member; and an electrical bias application unit (82, 83), characterized in that the electrical bias application unit (82, 83) is configured to simultaneously apply an electrical bias to both the transfer section and the bending roller to form an electric field to transfer toner adhered to the surface of the surface moving member from the surface moving member onto the belt member and an electric field to transfer toner adhering to a surface of the bending roller from the bending roller onto the belt member, and the transfer unit is further adapted such that the surface moving member rotates at least one full turn while cleaning is performed on the surface moving member and the bending roller by transferring the toner adhering to the surface of the surface moving member and the surface of the bending roller onto the belt member using the electrical bias applied from the electrical bias application unit (82, 83) to the transfer section and the bending roller, wherein a surface moving speed of the bending roller is equal to or greater than a surface moving speed of the surface moving member, wherein a circumferential length L1 of the surface moving member and a circumferential length L2 of the bending roller satisfying the relation L1≥L2. a belt member extended in a loop around a plurality of rollers and having a movable surface on which a toner image is transferred from an image carrier; a bending roller externally contacting the surface of the belt member to bend the belt member toward an interior of the loop and rotating in conjunction with movement of the surface of the belt member; a transfer section including one roller of the plurality of rollers and a rotatable surface moving member, the one roller located upstream from the bending roller and downstream from a transfer point at which the toner image is transferred from the image carrier onto the surface of the belt member in a surface moving direction of the belt member, the surface moving member facing the one roller of the plurality of rollers via the belt member, the transfer section transferring the toner image from the belt member onto a transfer material at a transfer nip formed as the surface moving member presses against the one roller via the belt member; and an electrical bias application unit (82, 83), characterized in that the electrical bias application unit (82, 83) is configured to simultaneously apply an electrical bias to both the transfer section and the bending roller to form an electric field to transfer toner adhered to the surface of the surface moving member from the surface moving member onto the belt member and an electric field to transfer toner adhering to a surface of the bending roller from the bending roller onto the belt member,