The invention discloses a developing unit and an imsge forming device having the same. The developing unit which has an improved structure to limit pressure between a developing member and a regulation roller to a regular range, and an image forming apparatus having the same are provided. A developing unit includes a developing member to develop an electrostatic latent image on a photoconductive medium using a developer, a regulation unit to press toward the developing member to regulate a layer of the developer supplied on the developing member, and a limit unit to limit pressure between the developing member and the regulation unit.