A toner cartridge for use in a printer includes a developing roller and an electrode. The toner cartridge is mountable in the printer by moving in a mounting direction and removable from the printer by moving in a removal direction. The developer roller supplies toner to a photosensitive member of the printer. The electrode is for electrically connecting with a bias supply electrode of the printer to supply a bias to the developing roller. The electrode moves, in a direction from outside the housing toward the interior of the housing and orthogonal to the mounting direction and the removal direction, under contact with the printer while the developing cartridge is being mounted in the printer. The electrode is electrically connected with the bias supply electrode of the printer while the developing cartridge is mounted in the printer.