PURPOSE: To unseal a toner cartridge without necessitating complicated constitution nor troublesome unsealing action and without scattering toner, to simplify and miniaturize structure by opening a toner discharge port by separating the opposed inner surfaces of a toner container itself.

CONSTITUTION: The toner discharge port where the inner surfaces 2a and 2b of the toner container 2 are mutually bonded is arranged above toner supply port 20. The hook 3b of an unsealing member 3 is hooked on a hook 23 attached to a side wall being the fixed side of a housing chamber 21, and the hook 4b of the other unsealing member 4 is hooked on a hook 25 attached to the opening/closing door 24 of the housing chamber 21. Next, the opening/closing door 24 of the housing chamber 21 is rotated with a hinge shaft 24a as center and closed. Since a space between both hooks 23 and 25 attached to the housing chamber 21 is extended, both unsealing members 3 and 4 are drawn apart from each other and the inner surfaces 2a and 2b of the container 2 are mutually separated, the toner discharge port is opened and the toner 5 in the container 2 is supplied to a developing device from the toner supply port 20.