A developing device (30) using a one-component developer or toner and applicable to image forming equipment for supplying the developer to a photoconductive element (20) disposed above the device. The device supplies a desired amount of toner to a toner supply roller (3) and a developing roller (2) at all times with no regard to the position thereof, thereby insuring stable images. Further, the device enhances free layout of the equipment and occupies a minimum of sectional area relative to the photoconductive element (20). <IMAGE>
