A remanufacturing method for a process cartridge includes (a) removing the second end cover at the other longitudinal ends of the drum frame, the developing frame and the developer frame; (b) removing a drum shaft rotatably supporting the drum; (c) separating the drum and the developing roller from each other; (d) moving the drum outwardly from the process cartridge, so that the drum is inclined, and then removing the drum from the drum frame; (e) inserting one end of a new drum such that a driving force receiving portion is exposed outside the drum frame, and inserting the drum shaft from outside of the drum frame; (f) opening a filling port provided in the developer accommodating portion, refilling the developer and then closing the filling port; and (g) fixedly mounting a second end cover to the other longitudinal ends of the drum frame, the developing frame and the developer frame.