An image forming apparatus includes: a photosensitive drum; a toner cartridge having a toner supply port; and a developing unit including: a developing roller; a developing frame; and a conveyance portion capable of conveying toner contained in the toner cartridge to the developing frame. The conveyance portion including: a coupling tube capable of being coupled to the toner cartridge and having a toner receiving port that faces the toner supply port in a state where the coupling tube is coupled to the toner cartridge; a conveyance tube fixed to the developing frame, the conveyance tube being movable with respect to the coupling tube, in a state where the coupling tube is coupled to the toner cartridge and the toner receiving port faces the toner supply port; and a shutter movable between an open position and a closed position.