PURPOSE: To provide a multicolor electrophotographic developing device and method for suppressing the peripheral electric field development of a complementary try level image.

CONSTITUTION: At a first developing station 32, a developing system with conductive magnetic brushes 35 and 36(CMB) is adopted and in a hybrid developing system using insulating magnetic brushes 37 and 38(IMB) and being for developing a synthetic try level xerographic latent image, at a second developing station 34, the conductivity of an IMB developer is ordered to be 10-13-10-15Ωcm, to prevent parasitic peripheral electric field development by an IMB developing system at the second developing station 34. Additionally, a scorotron corona electrifier 100 arranged between two developing housings 32 and 34 is used and an image developed at the first station 32 is electrified up to the same potential as that of a background (white level). Thus, at the second developing station 34, the parasitic peripheral electric field development with the IMB developer is prevented by <10-13Ωcm conductivity.