Embodiments of the present invention include an image bearing member arranged to bear an electrostatic latent image, a charging member contacting the image bearing member to charge a surface of the image bearing member with application of a DC voltage to the charging member, a current detection unit arranged to detect a DC current flowing in the charging member, and a control unit configured to control the voltage applied to the charging member, wherein a plurality of different DC voltages are successively applied to the charging member during a period of no image formation until a change amount of change in the DC current with respect to change in the DC voltage becomes not larger than a predetermined value, and the control unit controls a DC voltage applied to the charging member during a period of image formation based on a result detected by the current detection unit.