A developing cartridge that includes: a developing roller having a developing roller gear and a driving force transmitting unit; and an electrode member for applying a bias to a developing roller shaft. A direction of a driving force applied to the developing roller gear at an engagement portion between the developing roller gear and a transmission gear when the developing roller gear and the transmission gear rotate, and a direction of a force applied to the electrode member at a contact portion between a power supply member and the electrode member when the power supply member presses on the electrode member are substantially equal to a direction orthogonal to the axial direction of the developing roller shaft.