An additive manufacturing device comprising a powder feeding device (40, 40A, 40B, 40C) including a hopper (34, 34A) configured to accommodate powder, the hopper (34, 34A) including a discharge port for discharging the powder and the discharge port being provided in a lower portion of the hopper (34, 34A); and a conveyance device (41, 41B, 41C) including a conveyance surface disposed below the discharge port of the hopper (34, 34A) and configured to move the conveyance surface in a first direction and invert the conveyance surface in a front end portion, the conveyance device (41, 41B, 41C) including a belt (44, 44B, 44C) forming the conveyance surface and configured to move on an orbit in a loop shape along the first direction, and a moving mechanism configured to move the belt (44, 44B, 44C) on the orbit; wherein the hopper (34, 34A) includes a front wall portion positioned on a downstream side of the discharge port in the first direction, a predetermined gap is formed between a lower end of the front wall portion of the hopper (34, 34A) and the conveyance surface of the conveyance device (41, 41B, 41C), and the powder deposited on the conveyance surface is conveyed in the first direction by the conveyance device (41, 41B, 41C) with a thickness corresponding to the gap and dropped from the front end portion; the additive manufacturing device further comprising a work table provided below the front end portion of the conveyance device (41, 41B, 41C) and having an upper surface where the powder is placed; a modeling surface exposed upward beside the work table; an application mechanism movable onto the modeling surface from the upper surface of the work table and configured to deposit the powder on the modeling surface and level the powder; and a beam emission unit configured to emit a beam toward the powder fed onto the modeling surface by the application mechanism, the additive manufacturing device being characterized in that the gap between the lower end of the front wall portion and the conveyance surface changes in a second direction parallel to the conveyance surface and orthogonal to the first direction. a powder feeding device (40, 40A, 40B, 40C) including a hopper (34, 34A) configured to accommodate powder, the hopper (34, 34A) including a discharge port for discharging the powder and the discharge port being provided in a lower portion of the hopper (34, 34A); and a conveyance device (41, 41B, 41C) including a conveyance surface disposed below the discharge port of the hopper (34, 34A) and configured to move the conveyance surface in a first direction and invert the conveyance surface in a front end portion, the conveyance device (41, 41B, 41C) including a belt (44, 44B, 44C) forming the conveyance surface and configured to move on an orbit in a loop shape along the first direction, and a moving mechanism configured to move the belt (44, 44B, 44C) on the orbit; wherein the hopper (34, 34A) includes a front wall portion positioned on a downstream side of the discharge port in the first direction, a predetermined gap is formed between a lower end of the front wall portion of the hopper (34, 34A) and the conveyance surface of the conveyance device (41, 41B, 41C), and the powder deposited on the conveyance surface is conveyed in the first direction by the conveyance device (41, 41B, 41C) with a thickness corresponding to the gap and dropped from the front end portion; the hopper (34, 34A) includes a front wall portion positioned on a downstream side of the discharge port in the first direction, a predetermined gap is formed between a lower end of the front wall portion of the hopper (34, 34A) and the conveyance surface of the conveyance device (41, 41B, 41C), and the powder deposited on the conveyance surface is conveyed in the first direction by the conveyance device (41, 41B, 41C) with a thickness corresponding to the gap and dropped from the front end portion; the additive manufacturing device further comprising a work table provided below the front end portion of the conveyance device (41, 41B, 41C) and having an upper surface where the powder is placed; a modeling surface exposed upward beside the work table; an application mechanism movable onto the modeling surface from the upper surface of the work table and configured to deposit the powder on the modeling surface and level the powder; and a beam emission unit configured to emit a beam toward the powder fed onto the modeling surface by the application mechanism, the additive manufacturing device being characterized in that the gap between the lower end of the front wall portion and the conveyance surface changes in a second direction parallel to the conveyance surface and orthogonal to the first direction. a work table provided below the front end portion of the conveyance device (41, 41B, 41C) and having an upper surface where the powder is placed; a modeling surface exposed upward beside the work table; an application mechanism movable onto the modeling surface from the upper surface of the work table and configured to deposit the powder on the modeling surface and level the powder; and a beam emission unit configured to emit a beam toward the powder fed onto the modeling surface by the application mechanism, the additive manufacturing device being characterized in that the gap between the lower end of the front wall portion and the conveyance surface changes in a second direction parallel to the conveyance surface and orthogonal to the first direction.