A developing cartridge includes: a casing; a developing roller; a developing electrode; a gear; a rack gear including a protrusion; and a cam having first and second cam surfaces. The rack gear meshes with the gear and is movable in a direction from one end toward another end of the casing. The cam is movable from a first position to a second position. The first cam surface of the cam at the first position contacts the protrusion, and causes the cam to move to the second position as the rack gear moves in the direction in a state where the first cam surface is in contact with the protrusion. A second cam surface moves the developing electrode in a direction away from the cam different from moving directions of the rack gear and the cam while contacting the developing electrode as the cam moves to the second position.