An image forming apparatus that is more capable of preventing the occurrence of image quality deterioration caused by defective charging of a photoreceptor than the conventional one. As a charging device, there is used a member which has: a conductive sheet that causes the surface thereof applied with a predetermined bias to abut against the surface of the photoreceptor after passing through a primary transfer nip obtained by abutment between the photoreceptor and an intermediate transfer belt and before entering a development step performed by a developing device; a conductive brush member that applies a predetermined bias to the surface of the photoreceptor obtained after passing through the position of abutment with the sheet and before entering the development step; and a charging roller that uniformly charges the surface of the photoreceptor after passing through the position of abutment with the brush and before entering the development step. Furthermore, at least during a predetermined first period, a bias having a polarity same as the uniformly charging polarity of the photoreceptor is applied to the conductive sheet and brush member.