A method for manufacturing a screw-shaped tool for grinding a face gear with high precision. The tool is formed in such a manner that the diameter thereof gradually increases from an axial end to an intermediate section in the axial direction, and is used for cutting a face gear. The method includes setting up, on the basis of a prescribed pinion which is to mesh with the face gear to be machined, a virtual gear that is to mesh with the prescribed pinion, and has a greater number of teeth than the prescribed pinion; setting up, on the basis of the virtual gear, a virtual inner gear which has the same number of teeth as the virtual gear, said teeth being on the inside; and setting up, on the basis of the virtual inner gear, a screw-shaped grindstone having various elements that are used for cutting the virtual inner gear.