There is provided a manufacturing method of a three-dimensional shaped object, the method being capable of reducing a warp deformation of the three-dimensional shaped object. The manufacturing method according to an embodiment of the present invention produces a three-dimensional shaped object by alternate repetition of a powder-layer forming and a solidified-layer forming by light beam irradiation, wherein as a platform for the three-dimensional shaped object, a plate laminate body comprising a dummy solidified layer and a base plate for the shaped object is used, and the dummy solidified layer is formed on one of principal surfaces of the base plate, whereas the three-dimensional shaped object is manufactured on the other of the principal surfaces of the base plate.