An image forming apparatus including a movable belt member; rotatable first and second image bearings; first and second transfer members for electrostatically transferring the toner image from the first and second image bearing members, respectively, onto the belt member in contact with the belt member. The first and the second transfer members are disposed so that a position of a first end portion of a first contact portion between the first transfer member and the belt member on at least one side of the first contact portion with respect to a rotational axis direction of the first image bearing member and a position of a second end portion of a second contact portion between the second transfer member and the belt member on the same side as the at least one side of the first contact portion are substantially different from each other with respect to the rotational axis direction.