A toner cartridge of an electrophotographic image forming apparatus. The toner cartridge of the electrophotographic image forming apparatus includes a developing roller that develops an electrostatic latent image formed on an outer circumferential surface of a photosensitive drum, a toner supplying roller that supplies toner onto the developing roller, a seal bracket that is installed above and apart from the toner supplying roller, an outer seal film including an end adhered to the seal bracket and the other end contacting an outer circumference of the developing roller, and an inner seal film that is adhered to an inner surface of the seal bracket so that an end of the inner seal film contacts an outer circumference of the supplying roller.