An image forming apparatus includes a transfer member onto a front side of which an image is transferred, a rotary member around which the transfer member is wrapped, a guide member provided at an end portion of an axial direction of the rotary member, a regulating member, a first reference mark, a second reference mark, a first detector, a second detector, and a controller. The regulating member is located on a reverse side of the transfer member, and restricts skew of the transfer member by contacting the guide member. The first and second reference marks are on edge sides of the transfer member in the axial direction of the rotary member. The first and second detectors detect the first and second reference marks, respectively. The controller controls alignment of the image on the transfer member in accordance with a detection result of the first and second detectors.