A method of refurbishing a process cartridge includes removing first and second side plates, a charging unit removing step, a drum removing step, a drum attaching step, a charging unit attaching step, and a positioning step of attaching the first and second side plates to the development unit, to which the drum and the charging unit are attached, positioning the development and charging units by the first side plate as well as movably supporting the drum in a direction perpendicular to the lengthwise direction, and positioning the development and charging units and the drum by the second side plate. Another reproducing method includes opening an open/close shutter of a developing agent replenishing port, evacuating the developing agent in the development unit from the development agent replenishing port, filling a new developing agent from the developing agent replenishing port, and closing the open/close shutter.