An image forming apparatus includes an image bearing member, an intermediate transfer belt, and current supply devices. If (i) a current balance of a current supplied to the intermediate transfer belt is Ia-Ib where Ia is a sum of current densities of positive currents supplied from an outer to an inner peripheral surface of the intermediate transfer belt and Ib is a sum of current densities of positive currents supplied from the inner to the outer peripheral surface and (ii) an electric resistance of the intermediate transfer belt relative to the current balance is larger when the current balance is a negative of a predetermined value than when it is a positive of the predetermined value, a control unit performs constant current control on a discharge current supplied to the intermediate transfer belt during a print job such that, based on current supply detection, the current balance is positive.