A manufacturing method of a three-dimensional shaped object, comprising: a first step of depositing powder to form a powder layer; and a second step (S6, S7) of scanning and irradiating an energy beam to the powder layer to melt and then solidifying the powder layer to form a solidified layer; wherein the energy beam is irradiated to a part of the powder layer corresponding to either one area among a contour area (70-1A, 70-2A) including a surface of the shaped object and an inner-solid area inside of the contour area in advance and the energy beam is irradiated to a part of the powder layer corresponding to the other area (70-1B, 70-2B) later, wherein the first and second steps (S5, S6, S7) are alternately and repeatedly executed to form a three-dimensional shaped object by laminating a plurality of solidified layers, wherein the energy beam is scanned such that an irradiation starting point of the energy beam for forming an upper solidified layer among the plurality of laminated solidified layers does not overlap with an irradiation starting point of the energy beam for forming a lower solidified layer in a view from a lamination direction, wherein the upper solidified layer and the lower solidified layer are subsequent layers, characterised in that the energy beam is scanned such that a boundary between the contour area and the inner-solid area included in the upper solidified layer does not overlap with a boundary between the contour area and the inner-solid area included in the lower solidified layer in the view from the lamination direction, and the energy beam is scanned such that widths (W6, W5) of the contour areas of the upper and lower solidified layers are differentiated in a case where t/tanθ is smaller than a spot diameter of the energy beam or in a case where t/tanθ is 0.2 mm or less, where θ is an angle formed between a side surface of the three-dimensional shaped object and a main surface of the solidified layer and t is a thickness of one layer of the solidified layers. a first step of depositing powder to form a powder layer; and a second step (S6, S7) of scanning and irradiating an energy beam to the powder layer to melt and then solidifying the powder layer to form a solidified layer; wherein the energy beam is irradiated to a part of the powder layer corresponding to either one area among a contour area (70-1A, 70-2A) including a surface of the shaped object and an inner-solid area inside of the contour area in advance and the energy beam is irradiated to a part of the powder layer corresponding to the other area (70-1B, 70-2B) later, wherein the first and second steps (S5, S6, S7) are alternately and repeatedly executed to form a three-dimensional shaped object by laminating a plurality of solidified layers, wherein the energy beam is scanned such that an irradiation starting point of the energy beam for forming an upper solidified layer among the plurality of laminated solidified layers does not overlap with an irradiation starting point of the energy beam for forming a lower solidified layer in a view from a lamination direction, wherein the upper solidified layer and the lower solidified layer are subsequent layers, characterised in that the energy beam is scanned such that a boundary between the contour area and the inner-solid area included in the upper solidified layer does not overlap with a boundary between the contour area and the inner-solid area included in the lower solidified layer in the view from the lamination direction, and the energy beam is scanned such that widths (W6, W5) of the contour areas of the upper and lower solidified layers are differentiated in a case where t/tanθ is smaller than a spot diameter of the energy beam or in a case where t/tanθ is 0.2 mm or less, where θ is an angle formed between a side surface of the three-dimensional shaped object and a main surface of the solidified layer and t is a thickness of one layer of the solidified layers.