A lamination molding apparatus includes an irradiator, a processing unit, and a cooling device. The irradiator irradiates a material layer with a beam to form a solidified layer. The processing unit includes a processing head having a tool that performs processing on the solidified layer, and a processing head driver moving the processing head at least in a horizontal direction. The cooling device is provided in the processing head and cools at least a part of a solidified body including an upper surface to a predetermined cooling temperature, and the solidified body is formed by laminating the solidified layer. The cooling device includes a cooling plate having a cooling surface being cooled to the cooling temperature, and the cooling surface is in close contact with the upper surface of the solidified body in a recumbent state with the cooling surface along the horizontal direction.