A remanufacturing method for a process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, including (a) a frame separating step of separating the first frame and the second frame from each other; (b) a developing blade dismounting step of dismounting, from the second frame, a developing blade; (c) a sealing material mounting step of mounting a sealing material between the second frame and the developing blade; (d) a developer filling step of filling the developer into a developer accommodating portion of the second frame through a developer supply opening for supplying, to a developing roller, the developer accommodated in the developer accommodating portion; (e) a developing blade mounting step of mounting the developing blade to the second frame; and (f) a frame coupling step of the coupling the first frame and the second frame.