An image forming apparatus includes an image bearing member on which an electrostatic image is to be formed; a developing device for accommodating a developer including toner and a carrier and for developing the electrostatic image with the developer; a developer supply container, detachably mountable to a main assembly of the image forming apparatus, for accommodating a supply developer including the toner; a detecting device for detecting a toner content of the developer in the developing device; a supply control device for controlling an operation of supplying the supply developer into the developing device on the basis of a detection result of the detecting device and a density target value; a memory element, provided on the developer supply container, for storing information relating to elapse time from a manufacturing date of the supply developer; and a controller for determining the density target value in accordance with the information, wherein the supply control device controls the supply operation on the basis of the detection result of the detecting device and the density target value determined by the controller.