To make the direction of an angle well understandable even if a position of a filing cutter does not exist on its line by displaying a parallel line and an angle line on the left of a point, and displaying a parallel line and an angle line on the right of the point.

When a pedestal is used, it becomes a stong stabilizer by inserting a connecting plate lug 14 into a lug opening part 15. By a hinge, a receiving shaft 31 is arranged in a position of a point in a central part of the pedestal 4. A parallel groove 32 and an angle groove 33 are arranged on its left. A parallel groove 32 and an angle groove 33 are also arranged on the right of the receiving shaft 31. A receiving shaft opening part 18 is arranged on the right of the receiving shaft 31, and when the pedestal 4 is folded up, the receiving shaft 31 is bent by the hinge, and is housed. A chain saw is fixed, and when a file is set going along the angle groove 33, a cutter becomes complete, and the teeth of the saw can be excellently set.