An additive manufacturing method of depositing weld beads formed by melting and solidifying a filler metal while moving a welding torch attached to a robot tip shaft, the additive manufacturing method comprising: a step of measuring a shape profile (Pf) of an existing weld bead by a non-contact shape sensor provided on the robot tip shaft integrally with the welding torch, during manufacture of an additively-manufactured object by forming the weld beads, based on a deposition track plan that defines a target position of the welding torch and a shape of the weld beads; a step of extracting first geometric information of a bead shape from the shape profile (Pf) and the target position of the welding torch; a step of extracting second geometric information corresponding to the first geometric information from the deposition track plan and calculating a deviation amount (ΔH) between the first geometric information and the second geometric information; a step of updating the deposition track plan by changing at least one of a bead height (Bh) and a bead width (Bw) in a cross section perpendicular to a bead longitudinal direction of the weld bead defined by the deposition track plan, according to the deviation amount (ΔH); and a step of changing a welding condition according to an update result of the deposition track plan, wherein the first geometric information and the second geometric information include information on at least one of a geometric feature point near the target position of the welding torch, the bead height (Bh), the bead width (Bw), a bead cross-sectional area of the weld bead, or a cross-sectional shape approximation curve (Cpf) indicating a bead outer shape of the weld bead, and the geometric feature point includes any one of an apex of a convex shape of the existing weld bead, an end point of a narrowed portion formed by recessing a bead outer surface inward between the weld bead and another weld bead adjacent to the weld bead, or a point (P3a) where an end portion of the weld bead in a width direction and a lower layer surface on which the weld bead (B2 is formed intersect. a step of measuring a shape profile (Pf) of an existing weld bead by a non-contact shape sensor provided on the robot tip shaft integrally with the welding torch, during manufacture of an additively-manufactured object by forming the weld beads, based on a deposition track plan that defines a target position of the welding torch and a shape of the weld beads; a step of extracting first geometric information of a bead shape from the shape profile (Pf) and the target position of the welding torch; a step of extracting second geometric information corresponding to the first geometric information from the deposition track plan and calculating a deviation amount (ΔH) between the first geometric information and the second geometric information; a step of updating the deposition track plan by changing at least one of a bead height (Bh) and a bead width (Bw) in a cross section perpendicular to a bead longitudinal direction of the weld bead defined by the deposition track plan, according to the deviation amount (ΔH); and a step of changing a welding condition according to an update result of the deposition track plan, wherein the first geometric information and the second geometric information include information on at least one of a geometric feature point near the target position of the welding torch, the bead height (Bh), the bead width (Bw), a bead cross-sectional area of the weld bead, or a cross-sectional shape approximation curve (Cpf) indicating a bead outer shape of the weld bead, and the geometric feature point includes any one of an apex of a convex shape of the existing weld bead, an end point of a narrowed portion formed by recessing a bead outer surface inward between the weld bead and another weld bead adjacent to the weld bead, or a point (P3a) where an end portion of the weld bead in a width direction and a lower layer surface on which the weld bead (B2 is formed intersect. an apex of a convex shape of the existing weld bead, an end point of a narrowed portion formed by recessing a bead outer surface inward between the weld bead and another weld bead adjacent to the weld bead, or a point (P3a) where an end portion of the weld bead in a width direction and a lower layer surface on which the weld bead (B2 is formed intersect.