There is provided a method for manufacturing a three-dimensional shaped object, the method comprising the repeated steps of: (i) forming a solidified layer by irradiating a predetermined portion of a powder layer with a light beam, thereby allowing a sintering of the powder in the predetermined portion or a melting and subsequent solidification thereof; and (ii) forming another solidified layer by newly forming a powder layer on the resulting solidified layer, followed by the irradiation of a predetermined portion of the powder layer with the light beam, wherein a part of a surface portion of the three-dimensional shaped object is formed as a low-density solidified portion whose solidified density ranges from 50% to 90% so that an application of pressure can be performed by a gas flowing through the low-density solidified portion.