A machining-path generation method for generating a machining path of an additive manufacturing device to perform additive machining by controlling a machining head that includes a nozzle to supply a columnar build material to a machining region on a target surface, and a beam nozzle to irradiate the machining region with a beam that melts the build material supplied to the machining region, the nozzle and the beam nozzle being provided non-coaxially with each other, the machining-path generation method being characterized in that the machining head further includes a gas nozzle spraying shield gas toward the machining region, and in that a relative positional relation between the nozzle, the beam nozzle and the gas nozzle is fixed by the machining head, the machining-path generation method being further characterized in that an angle of an advancement direction of the machining head relative to a direction in which the columnar build material is supplied to the machining region is changed by a given angle or greater on the way through the machining path as the machining head moves along the machining path, and further characterized by a step of obtaining manufacturing-shape data that represents a manufacturing-target shape; a step of generating a basic machining path from the manufacturing-shape data; and a step of generating data of a plurality of divided machining paths from the basic machining path in such a manner that on the divided machining paths, the angle of an advancement direction of the machining head relative to a direction in which the columnar build material is supplied to the machining region falls within a predetermined range of allowable head angle, wherein the advancement direction of the machining head is determined by projecting the motion of the machining head onto a plane perpendicular to an irradiation direction of the beam. a nozzle to supply a columnar build material to a machining region on a target surface, and a beam nozzle to irradiate the machining region with a beam that melts the build material supplied to the machining region, the nozzle and the beam nozzle being provided non-coaxially with each other, the machining-path generation method being characterized in that the machining head further includes a gas nozzle spraying shield gas toward the machining region, and in that a relative positional relation between the nozzle, the beam nozzle and the gas nozzle is fixed by the machining head, the machining-path generation method being further characterized in that an angle of an advancement direction of the machining head relative to a direction in which the columnar build material is supplied to the machining region is changed by a given angle or greater on the way through the machining path as the machining head moves along the machining path, and further characterized by a step of obtaining manufacturing-shape data that represents a manufacturing-target shape; a step of generating a basic machining path from the manufacturing-shape data; and a step of generating data of a plurality of divided machining paths from the basic machining path in such a manner that on the divided machining paths, the angle of an advancement direction of the machining head relative to a direction in which the columnar build material is supplied to the machining region falls within a predetermined range of allowable head angle, a step of obtaining manufacturing-shape data that represents a manufacturing-target shape; a step of generating a basic machining path from the manufacturing-shape data; and a step of generating data of a plurality of divided machining paths from the basic machining path in such a manner that on the divided machining paths, the angle of an advancement direction of the machining head relative to a direction in which the columnar build material is supplied to the machining region falls within a predetermined range of allowable head angle, wherein the advancement direction of the machining head is determined by projecting the motion of the machining head onto a plane perpendicular to an irradiation direction of the beam.