After having assembled an intermediate transfer assembly and an image carrier unit, an operator attaches a bearing to a hole section in a side frame, inserts one end of a pivotal shaft of an image carrier into the bearing attached to the hole section, turns the pivotal shaft with one end of the pivotal shaft attached to the bearing serving as a pivot, and runs the other end of the pivotal shaft through a notch in the side frame. The operator attaches a bearing to the other end of the pivotal shaft run through the notch from the axial direction of the pivotal shaft, and fixes the bearing onto the side frame by a fixing member.