In a developer container, a rotating shaft is rotatably supported by a casing and is rotationally driven. A flexible member has a leading edge portion which is connected to the rotating shaft and turns through a region extending over a supply port on an inner lower surface of the casing when the flexible member is rotated in association with the rotating shaft. A rotating plate is formed to project in a handguard-shape from a portion of the rotating shaft adjacent to the flexible member, has an outer edge portion along an edge of the supply port, and rotates in association with the rotating shaft.