A developer supplying device includes: a substantially cylindrical developer container having on its peripheral surface a spiral groove, and being rotatable to transport a developer therein by the groove; a supplying element in a form of an opening provided at the peripheral surface of the container to supply the developer therethrough; and a regulating device provided in the container, regulating an amount of the developer supplied from the supplying element, and being so formed to reduce a sectional area between the regulating device and an inner surface of the container in the vicinity of the supplying element. The supplying device can have a container-supporting device having a guide device for guiding the developer supplied by the supplying element; and a supplying element-covering device provided at the peripheral surface of the container, and being opened to uncover the supplying element when the latter confronts the guide device for supplying the developer. The supplying device also can have a ball-like stirring device included in and movable within the container in accordance with rotation thereof to stir the developer. The supplying device further can have a holding device capable of being inserted thereinto the container and having the guide device; a transporting device for transporting the developer supplied through the guide device for development; a drive device for rotating the container; and a connecting device provided at one side of the container for rotation of the container within the holding device by the drive device.