A developing device includes a case for housing a developer, a magnetic roller, an agitating member, a layer thickness restricting member and a plurality of projection members. The magnetic roller is arranged in the case, includes a rotary shaft and magnetically carries the developer on a circumferential surface. The agitating member is arranged to face the magnetic roller in the case, includes a shaft center and a screw forming portion arranged around the shaft center. The layer thickness restricting member restricts the layer thickness of the developer to a predetermined thickness. The plurality of projection members are arranged along a rotation axis direction of the magnetic roller to face the circumferential surface of the magnetic roller at a side upstream of the layer thickness restricting member in a rotating direction of the magnetic roller and comes into contact with the developer carried on the magnetic roller.