Layered molding device

An additive manufacturing apparatus comprising:

• an operation unit which includes a first part and a second part and is provided with a first opening between the first part and the second part, the first part and the second part that cover a part of a supply region facing a first direction and supplied with a powdery material, and that are aligned in a second direction intersecting with the first direction, the first opening extending in the first direction;
• a first face of the first part facing the second part, and provided with a second opening;
• a mover which moves the operation unit with respect to the supply region;
• a supplier which supplies an inert gas from the second opening to the first opening;
• and
• an irradiator which is spaced apart from the operation unit, and is capable of emitting an energy ray to the material in the supply region through the first opening, and changing a position with which the energy ray is irradiated.