A toner cartridge including a guide member that guides supplying operation of toner. The toner cartridge includes a housing, in which a toner of a predetermined color is filled, a first coupling portion and a second coupling portion within the housing that are formed at predetermined positions of an inner wall of the housing; a developing roller, part of which is exposed outside of the housing, installed rotatably on the housing to supply the toner to a photosensitive medium and to develop an image; a supplying roller that attaches the toner to the developing roller; and the guide member that guides the toner supply and is coupled to the first and second coupling portions. Both ends of the guide member are coupled to the first and second coupling portions such that the guide member is flexed when being installed in the housing.