The image forming apparatus includes an image bearing member for forming an electrostatic image, a developing apparatus for developing the electrostatic image on the image bearing member with a developer, a developer container for containing a replenishing developer, and dismountably mounted on a main body of the apparatus, and a developer replenishing apparatus for replenishing the replenishing developer in the developer container to the developing apparatus, wherein at least the image bearing member and the developing apparatus are provided in a cartridge which is dismountably mountable on the main body of the apparatus and the developer container is provided in a position not overlapping with a moving area of the cartridge in a dismounting or mounting operation of the cartridge.