A method for manufacturing an additively-manufactured object in which an additively-manufactured object comprising a protrusion extending in one direction is built by beads (55A - 55E) formed by melting and solidifying a filler metal (Fm), the method comprising: a slicing step of slicing a shape of the additively-manufactured object into a plurality of layers (H1 - H7) depending on a height (H) of the beads (55A - 55E) by using three-dimensional shape data of the additively-manufactured object ; a surface dividing step of dividing each of the layers (H1 - H7) into a plurality of regions (R) by applying a region (R) having a preset set shape to each of the sliced layers (H1 -H7); a connection line extracting step of determining a connection line (L) connecting adjacent regions (R) with each other from one end portion to the other end portion of the protrusion , in which an adjacent region (R) of the adjacent regions (R) is selected starting from another adjacent region (R) of the adjacent regions (R) in a preset set direction (A), wherein the preset set direction (A) is changed for selecting the adjacent region (R) adjacent to one of a left or right sides, when there is no adjacent region (R) which can be selected in the preset set direction (A); an extension direction estimating step of determining an extension direction (B) of the protrusion based on the connection line (L); a bead formation line determining step of determining a formation projected line (C) of the beads (55A - 55E) by dividing the sliced layers (H1 - H7) into a plurality of the beads (55A - 55E) along the extension direction (B); and a building step of building the additively-manufactured object by forming the beads (SSA - 55E) along the formation projected line (C) of the beads (SSA - 55E). a slicing step of slicing a shape of the additively-manufactured object into a plurality of layers (H1 - H7) depending on a height (H) of the beads (55A - 55E) by using three-dimensional shape data of the additively-manufactured object ; a surface dividing step of dividing each of the layers (H1 - H7) into a plurality of regions (R) by applying a region (R) having a preset set shape to each of the sliced layers (H1 -H7); a connection line extracting step of determining a connection line (L) connecting adjacent regions (R) with each other from one end portion to the other end portion of the protrusion , in which an adjacent region (R) of the adjacent regions (R) is selected starting from another adjacent region (R) of the adjacent regions (R) in a preset set direction (A), wherein the preset set direction (A) is changed for selecting the adjacent region (R) adjacent to one of a left or right sides, when there is no adjacent region (R) which can be selected in the preset set direction (A); an extension direction estimating step of determining an extension direction (B) of the protrusion based on the connection line (L); a bead formation line determining step of determining a formation projected line (C) of the beads (55A - 55E) by dividing the sliced layers (H1 - H7) into a plurality of the beads (55A - 55E) along the extension direction (B); and a building step of building the additively-manufactured object by forming the beads (SSA - 55E) along the formation projected line (C) of the beads (SSA - 55E). <EOS>