A toner cartridge includes a container main body includes a toner outlet, a shutter mechanism for opening and closing the toner outlet, a lever for operating the shutter mechanism, a lever locking mechanism, a lock releasing mechanism, and a prevention mechanism. The lever locking mechanism locks the lever so as to be inoperative while the toner outlet is closed. The lock releasing mechanism unlocks the lever locked by the lever locking mechanism in conjunction with installment of the container main body into the image forming device. The prevention mechanism prevents the container main body from being taken out of the image forming device while the container main body is installed in the image forming device, and the lever operates to open the toner outlet.