PURPOSE: To form a uniform thin layer of nonmagnetic toner on the surface of a nonmagnetic cylinder which faces an image carrier and to form an excellent picture, by arranging and fixing a magnetic field producing means only on the developer storage container side in the nonmagnetic cylinder which rotates along the image carrier.

CONSTITUTION: Carriers 11 and nonmagnetic toner 12 couples together weakly by electrostatic force in a developing container 14 and are attracted to the surface of a developing sleeve 8 by magnets 13-1W13-4 provided in the sleeve 8; and carrier particles 11 are scraped off by amagnetic blade 9 as the sleeve 8 rotates and the nonmagnetic toner 12 passes by the blade 9 to form the thin layer of the nonmagnetic toner 12 on the surface of the sleeve 8 which faces a photosensitive drum 1. All the magnets 13 are provided limitedly only in the developing container 14, so no carriers 11 are carried out of the blade part 9 and only nonmagnetic toner 12 is supplied to a development part.