An additive manufacturing apparatus includes: a chamber, including a front plate; a door, provided at an opening of the front plate; an irradiator; a gas supplier, supplying an inert gas to the chamber; and a gas discharger, discharging the inert gas from the chamber. The gas supplier includes a middle nozzle and a lower nozzle. The middle nozzle is provided so as to cross the opening when the door is closed, has one end swingably supported on the front plate, and swings independently of opening and closing of the door.