Tool path generation device and method

A tool path generation device (50) for generating a tool path for forming, in a workpiece material, a recessed portion that is defined by the overall shape of an area to be machined and a depth, said tool path generation device (50) comprising: a spiral machining path reference circle generation unit (4) which extracts a plurality of circular regions satisfying preset conditions from the overall shape of the area to be machined; a spiral machining path generation unit (6) which generates a tool path for machining, along a spiral path, either the plurality of circular regions extracted by the spiral machining path reference circle generation unit (4), or regions including the plurality of circular regions and the surroundings thereof, and which also generates a spiral region shape to be machined, which is obtained by removing the regions to be machined along the spiral tool path from the overall shape of the area to be machined; and a trochoidal machining path generation unit (7) which generates a tool path for machining a post-spiral-machining region shape to be machined.