A remanufacturing method includes dismounting, from one end of a drum frame, a supporting member while rotatably supporting one end of a drum and a developing device frame; separating the two frames; dismounting the drum; mounting one end of a fresh drum to the other end of the drum frame; a refilling developer into a developer accommodating portion of the separated developing device frame; and swingably connecting the developing device frame and the drum frame by mounting the supporting member to one end of the drum frame, while rotatably supporting, by the supporting member, the one end of the drum of the drum frame to which the fresh drum has been mounted and swingably supporting the one end of the developing device frame to the developer accommodating portion of which the developer has been refilled, by the drum frame.