A toner draining mechanism has a hollow member and a conveying member which is arranged in the hollow member and conveys toner. A toner draining port for draining the conveyed toner is formed in the hollow member. The toner draining port is formed above a bottom surface of the hollow member. Therefore, when a toner cartridge is exchanged, the toner near the toner draining port does not drop into an image forming apparatus. Thus, it is possible to prevent the toner from dirtying the inside of the image forming apparatus.