A method for manufacturing a three-dimensional shaped object wherein the warping of the base plate is suitably addressed. The method of the present invention comprises: (i) forming a solidified layer by irradiating a predetermined portion of a powder layer on a base plate with a light beam, thereby allowing sintering of the powder of the predetermined portion or melting and subsequent solidification thereof; and (ii) forming another solidified layer by newly forming a powder layer on the resulting solidified layer, and then irradiating another predetermined portion of the new powder layer with the light beam, the steps (i) and (ii) being repeatedly performed; wherein, prior to or upon the manufacturing of the three-dimensional shaped object, the base plate is subjected to a heat treatment, thereby causing the base plate to be warped, and at least a lower surface of the warped base plate is subjected to a flattening process.