An image forming apparatus has a charge roller, a charge erasing device and a preliminary voltage-applying member disposed around a rotationally movable photosensitive member. The charge roller subjects a surface of the photosensitive member to a charge process while contacting the surface of the photosensitive member. The charge erasing device is on an upstream side of the photosensitive member relative to the charge roller and erases the charged area in the photosensitive member. The preliminary voltage-applying member is on an upstream side of photosensitive member relative to the charge erasing device and applies to the surface of the photosensitive member a voltage of the same polarity as the voltage applied from the charge roller to the surface, while contacting the surface. The preliminary voltage-applying member is reciprocated along the surface of the photosensitive member and in a direction orthogonal to the movement direction of the surface.