A method of reproducing a process cartridge or a developing apparatus includes the step of removing a supporting member from a developing frame body, the step of separating a developer container and the developing frame body from each other in a joint portion wherein the developer container and the developing frame body are joined together, the sticking step of sticking a seal member on an opening portion for supplying a developer in the separated developer container to close the opening portion, the developer refilling step of refilling the developer container with the developer, the step of recoupling the developer container and the developing frame body together thereafter, and the step of reattaching the supporting member onto one of the developer container and the developing frame body. As a result, the recycling of the developing apparatus or the process cartridge can be effected easily.