The invention discloses a three-dimensional shaping method in which after formation of a powder layer (4) with a predetermined thickness, a step for sintering the powder layer (4) by an optical beam is performed at a predetermined number of times and, thereafter, a periphery thereof is cut, comprising that a control system stores in advance a region at coordinate positions in a horizontal direction and a height direction in which an undercut angle formed between an upper face and a lower inclined face at the edge of an expected sintered part is equal to or less than a predetermined extent corresponding to a cause for forming a raised sintered portion (12) on each layer, and when the region at the coordinate positions is present on an individual layer to be sintered, the control system temporarily stocks the region at the coordinate positions, and also after sintering of the layer concerned is completed, at an intermediate height position between the position of the surface on which the sintering concerned has been completed and the lowest position of a powder supplying blade (2) moving in the horizontal direction for forming a powder layer (4) on a next layer on the upper side of the layer concerned, a rotating cutting tool (3) travels around the region at the coordinate position in the horizontal direction and an outer peripheral vicinity thereof according to instructions of the control system, thereby, in the case that a raised sintered portion (12) is formed which is positioned on the upper side of the region at the coordinate position, the rotating cutting tool (3) cuts the raised the sintered portion entirely or partially with detecting the cause for forming a raised sintered portion (12) on each layer and without detecting the raised sintered portion (12).