An image forming apparatus includes a developing device for developing an electrostatic image with a developer; a developer amount detecting device for detecting an amount of a developer in the developing device; a developer consumption amount calculating device for calculating a consumption amount of the developer on the basis of image information of the electrostatic image; a developer supplying device for supplying the developer to the developing device; a control device for controlling a developer supply operation to the developing device by the developer supplying device, wherein the control device controls the developer supply device to supply a predetermined amount of the developer every time an integrated value of the consumption amount of the developer exceeds a supply threshold, and corrects the supply threshold on the basis of information relating to an amount of the developer in the developing device detected by the developer amount detecting device.