Provided is an image forming apparatus including a unit for controlling each voltage value of peak-to-peak voltages of DC and AC voltages applied to a charging unit for charging an image bearing member, in which a residual charge eliminating unit conducts charge elimination on a surface of the image bearing member while at least the charging unit undergoes an application of the AC voltage including the peak-to-peak voltage that is, in the case of setting at Vth a discharge start voltage to the image bearing member when applying the DC voltage to the charging unit, twice or smaller than this discharge start voltage Vth. With this image forming apparatus, it is possible to restrain an occurrence of a defect in an image which is attributable to an instability of a charging potential on the image bearing member by stabilizing a potential on the image bearing member at zero even in a case where the AC voltage applied to the charging unit for the image bearing member is the peak-to-peak voltage that is twice or smaller than Vth.