A developing device is provided that facilitates developing agent delivery upward. A cartridge includes a developing roller, a supply roller, and a container disposed below the supply roller. The container can have an upper portion formed with an opening having upper and lower edges. A conveying member can be rotatably disposed and in rotational contact with an inner surface of the container for delivering the developing agent upward. The developing agent container can include a first wall portion for receiving the developing agent through the opening. The first wall portion extends from the lower edge in a downstream direction with respect to a rotational direction of the conveying member toward a bottommost portion of the supply roller. The container also includes a second wall portion extending from the upper edge in an upstream direction. The conveying member can be in simultaneous sliding contact with the first and the second wall portions.