An additive manufacturing device performs manufacturing of an additively manufactured article by supplying a powder material to an irradiation region of an electron beam, laying and leveling the powder material, irradiating the powder material with the electron beam, and melting the powder material. The additive manufacturing device determines whether or not the powder material has scattered during manufacturing of the article. When it is determined that the powder material has scattered, an irradiation region R is heated by a heater before a new powder material is supplied to the irradiation region R. Manufacturing of the article is restarted after the new powder material has been supplied to the heated irradiation region.