Abstract: A developing apparatus comprises a container in which a developer composed of a mixture of carrier and toner is stored and a screw conveyor for transferring and stirring the developer is disposed. The screw conveyor has a stirring blade formed in a spiral shape, and the stirring blade is cut out at nearly the center of the screw conveyor so that stagnation of the developer takes place at that interrupted portion thereof. A level sensor is disposed so as to be able to detect the level of the developer at that interrupted portion. In the interrupted portion, since stagnation of the developer takes place, pulsation of the developer produced in the case of the screw conveyor having a continuous stirring blade is suppressed, and thereby a level of the developer can be detected more accurately.