In the developing apparatus of the present invention, a first agitating and carrying screw has in its vicinity a toner supply opening, through which toner is supplied, on an upstream side in a direction to which developer is carried, the first agitating and carrying member being provided farther from the developer holder than the second agitating and carrying member. A partition plate which partitions an inside of the developer containing tank so as to form first and second carrying paths includes one or more cuts provided from a center section in a longitudinal direction to an end section on a side where the toner supply opening is provided. Therefore, the developer can be returned from the second carrying path to the first carrying path through a second communicating path and the one or more cuts. Consequently, it becomes possible to shorten a time for uniformly mixing the developer and to improve (i) a developer agitating performance and (ii) a toner charging performance of the developing apparatus. This allows to supply stable toner excellent in electrostatic property.