In a three-dimensional shaping device, a region of an elevatable/lowerable table 2 for forming a powder layer and a region of a powder supply device are divided by a shield plate, an inert gas injection port is provided in the former region, the shield plate can be freely opened or closed so that a powder spraying squeegee traveling on the table is passed through, or a pipe which supplies powder from the powder supply device to the powder spraying squeegee which has traveled to the side of the shield plate penetrates through the shield plate, or a part of the shield plate is the powder supply port for the powder spraying squeegee which has traveled to the side of the shield plate and the pipe protrudes at a lower part and a sintering device applies a laser beam via a transparent region in a ceiling of a chamber.