To achieve a developing device for forming a high quality image having no developing unevenness with an easy constitution.

A retention preventing section 106 is disposed in an abutting part of an inner surface of a developer storage tank 101 on the surface on the upstream side of the rotating direction of a developing roller 104 in a doctor blade 105. The angle between the surface on the side of the developing roller 104 in the retention preventing section 106 and the surface on the upstream side of the rotating direction of the developing roller 104 in a doctor blade 105 is made larger than the angle between the concentric circle of the cross section perpendicular to the extending direction of the developing roller 104 and the surface on the upstream side of the rotating direction of the developing roller 104 in the doctor blade 105, in the abutting part of the surface on the side of the developing roller 104 in the retention preventing section 106 on the surface on the upstream side of the rotating direction of the developing roller 104 in the doctor blade 105.