A toner cartridge comprises a toner cartridge main body which houses toner, a discharging opening which supplies the toner housed in the toner cartridge main body to an image forming apparatus, a shutter which opens the discharging opening when the toner cartridge main body is inserted in the image forming apparatus and closes the discharging opening when the toner cartridge main body is removed from the image forming apparatus, and a notifying member which includes a first protrusion provided in the toner cartridge main body, to show that the toner cartridge main body is set in the image forming apparatus by temporary engaging with a second protrusion provided in the image forming apparatus at the same time when the shutter completes the opening of the discharging opening, when the toner cartridge main body is inserted in the image forming apparatus.