A remanufacturing method for remanufacturing a second developing device from a first developing device , the first developing device including a frame provided with a developer accommodating chamber for accommodating a developer (TY, TM, TC, TK), the frame having an opening for communicating the developer accommodating chamber with the outside of the frame ; and a first cap member configured to seal the opening , the first cap member being adhesively bonded to a first region of the frame with a first adhesive capable of dissolving the frame , and the remanufacturing method being characterized by comprising: a removing step of removing the first cap member from the first region , to which the first cap member is adhesively bonded, such that the first region remains on the frame and a rough surface is formed in the first region ; a filling step of filling the developer accommodating chamber with the developer (TY, TM, TC, TK); and a sealing step of bonding a second cap member different from the first cap member to a second region (H) of the frame different from the first region to seal the opening with the second cap member , wherein the second region (H) is located closer to the opening than the first region so as to be located on a radially inner side of the opening of the first region on an outer surface of the frame . the first developing device including a frame provided with a developer accommodating chamber for accommodating a developer (TY, TM, TC, TK), the frame having an opening for communicating the developer accommodating chamber with the outside of the frame ; and a first cap member configured to seal the opening , the first cap member being adhesively bonded to a first region of the frame with a first adhesive capable of dissolving the frame , and the remanufacturing method being characterized by comprising: a removing step of removing the first cap member from the first region , to which the first cap member is adhesively bonded, such that the first region remains on the frame and a rough surface is formed in the first region ; a filling step of filling the developer accommodating chamber with the developer (TY, TM, TC, TK); and a sealing step of bonding a second cap member different from the first cap member to a second region (H) of the frame different from the first region to seal the opening with the second cap member , wherein the second region (H) is located closer to the opening than the first region so as to be located on a radially inner side of the opening of the first region on an outer surface of the frame . a removing step of removing the first cap member from the first region , to which the first cap member is adhesively bonded, such that the first region remains on the frame and a rough surface is formed in the first region ; a filling step of filling the developer accommodating chamber with the developer (TY, TM, TC, TK); and a sealing step of bonding a second cap member different from the first cap member to a second region (H) of the frame different from the first region to seal the opening with the second cap member , wherein the second region (H) is located closer to the opening than the first region so as to be located on a radially inner side of the opening of the first region on an outer surface of the frame . <EOS>