PURPOSE: To improve the ability of a developing device in with mode to convey a developer by providing a magnet roll for developer conveyance between a developing roll and a paddle for supplying the developer thereto, and supplying the developer onto the developing roll.

CONSTITUTION: The developer 3 scooped up with the paddle 4 is conveyed by the magnet roll 5 for developer conveyance to a magnet N3 positioned at the upper part of the back surface of an upper developing roll 2a, and then guided to magnets S2 and N2, and S1 and N1 provided to the upper developing roll 2a and magnets N2 and S2, N1 and S1, and N3 provided to a lower developing roll 2b, so that it falls between a photosensitive body 1 and the developing rolls 2a and 2b. Therefore, the back surface conveyance of the developer 3 by the developing rolls 2a and 2b is eliminated, and it is therefore unnecessary to arrange magnets on the back surface sides of the developing rolls 2a and 2b, i.e. between magnets N3 and N1 of the upper developing roll 2a and magnets N2 and N3 of the lower developing roll 2b.