Abstract: An addictive manufactured object manufacturing method includes: a shell portion forming step of additively forming a shell portion corresponding to an outer portion of an addictive manufactured object by a shell portion beads formed by weaving welding; and a core portion forming step of additively forming a core portion corresponding to an inner portion of the addictive manufactured object by a core portion bead formed by welding.

Abstract: To prevent metal vapor and spatter from adhering to an optical system. A vacuum laser processing device includes: a laser beam irradiation unit having an optical system configured to emit a laser beam and an irradiation chamber through which the emitted laser beam passes; a construction chamber to which the irradiation chamber of the laser beam irradiation unit is connected, and in which an object to be processed to be constructed by the laser beam is positioned; a vacuum device unit configured to produce a vacuum in the interior of the construction chamber; and a gas supply unit having a gas nozzle configured to inject cross jet gas toward the laser beam at an irradiation port, which is the outlet of the laser beam of the irradiation chamber.