PURPOSE: To provide a process cartridge excellent in operability at the time of supplying developer, excellently initializing the developer and surely stirring and carrying the developer.

CONSTITUTION: In this process cartridge formed so that a developing unit 3 for developing an electrostatic latent image formed on a photoreceptor drum 1 to be a developed image may be integrally disposed at a specified position; a developer preset part 9 for sealing the developer is integrally provided with the process cartridge(upper cartridge case) on the upper part of the developing part of the developing unit 3 and a partition plate 10 making the developer in a sealed state is provided between the preset part 9 and the developing part.