A three-dimensional molding method in which a step of sintering a powder layer with a laser light or an electron beam after a flat surface has been formed by sliding of a squeegee against the powder layer is repeated in a prescribed number of times, and then the periphery is cut, in order to mold both the object 1 to be molded and a support structure 2 that supports the lower side of the object 1 from below and is intended to be removed after molding, wherein in the support structure 2, the upper parts of the struts connected to the object 1 to be molded employ truncated circular conic shapes or partial truncated circular conic shapes that are reduced in diameter toward the top.