A laminate shaping method of shaping a three-dimensional shaped object formed by sequentially laminating a plurality of metal layers, the method comprising: a unit step repeatedly performed, the unit step including a step of forming a laminate shaped portion by laminating metal layers formed of weld beads, and a step of forming a processed side surface by cutting a shaped portion side surface of the laminate shaped portion that faces a second direction intersecting a first direction in which the metal layers are laminated, wherein, in the step of forming the processed side surface, the shaped portion side surface is cut so that a receiving portion projecting in the second direction with respect to the processed side surface, the receiving portion is formed at an uppermost layer of the laminate shaped portion in the first direction, when the unit step is repeated, in the step of forming the laminate shaped portion, a new metal layer is laminated so as to overlap an upper surface of the receiving portion in the first direction, characterized in that the shaped object is formed in a cylindrical shape centered on an axis extending in the first direction so as to allow a fluid to flow through an inside of the shaped object, in the step of forming the processed side surface, an inner circumferential surface of the shaped object facing toward an inside in a radial direction and an outer circumferential surface of the shaped object facing toward an outside in a radial direction are formed by the processed side surfaces, and the processed side surface is formed by cutting the shaped portion side surface in a flow direction of the fluid flowing through the inside of the shaped object. a unit step repeatedly performed, the unit step including a step of forming a laminate shaped portion by laminating metal layers formed of weld beads, and a step of forming a processed side surface by cutting a shaped portion side surface of the laminate shaped portion that faces a second direction intersecting a first direction in which the metal layers are laminated, a step of forming a laminate shaped portion by laminating metal layers formed of weld beads, and a step of forming a processed side surface by cutting a shaped portion side surface of the laminate shaped portion that faces a second direction intersecting a first direction in which the metal layers are laminated, wherein, in the step of forming the processed side surface, the shaped portion side surface is cut so that a receiving portion projecting in the second direction with respect to the processed side surface, the receiving portion is formed at an uppermost layer of the laminate shaped portion in the first direction, when the unit step is repeated, in the step of forming the laminate shaped portion, a new metal layer is laminated so as to overlap an upper surface of the receiving portion in the first direction, characterized in that the shaped object is formed in a cylindrical shape centered on an axis extending in the first direction so as to allow a fluid to flow through an inside of the shaped object, in the step of forming the processed side surface, an inner circumferential surface of the shaped object facing toward an inside in a radial direction and an outer circumferential surface of the shaped object facing toward an outside in a radial direction are formed by the processed side surfaces, and the processed side surface is formed by cutting the shaped portion side surface in a flow direction of the fluid flowing through the inside of the shaped object.