An image forming apparatus includes a process cartridge with an image bearing member configured to bear an image on a surface thereof. A developing device is configured to develop the image formed on the image bearing member by using a developer accommodated in a chamber thereof. The developing device includes a developer bearing member configured to bear the developer on a surface thereof to transfer the developer to the image formed on the image bearing member. A conveying member is configured to agitate and convey the developer in the chamber to the developer bearing member. A regulating member held in contact with the developer brought up from the chamber onto the surface of the developing roller is configured to uniformly distribute the developer on the surface of the developer bearing member.