An image forming unit has a rotatable electrostatic latent image carrier, a charge member positioned to contact the electrostatic latent image carrier and charge a surface of the electrostatic latent image carrier, and a developing part, which supplies a developer to the electrostatic latent image carrier for obtaining a developer image. The charge member includes a conductive elastic layer and a surface layer formed on a circumferential surface of the conductive elastic layer. The surface layer contains particles having an average particle size of 5 μm-20 μm; and a ratio of a surface area per unit area of the surface layer is in a range from 1.5 to 3.0.