An image forming apparatus that includes: an image carrier; a developing cartridge detachably mountable with respect to the image carrier; a processing device to which voltage acting between the image carrier and the processing device is applied; and a first electrode, wherein the developing cartridge further includes: a developing roller on which toner is capable of being held; and a second electrode capable of being electrically connected with the first electrode when the developing cartridge is mounted with respect to the image carrier, the processing device further includes: a third electrode capable of being electrically connected with the second electrode when the developing cartridge is mounted with respect to the image carrier, wherein the second electrode positions the developing cartridge in an axial direction of the developing roller.