PURPOSE: To effect indexing of a cutting position easily regarless of a cutting angle and to make a cutter effective particularly for a production of small quantity in many varieties by definning an intersecting point of an always constant moving trace of the cutter and a center line of a revolving shaft as a standard point.

CONSTITUTION: A pivotting arm 6 is attached to a lower end of a revolving shaft 5 supportingly received by a shaft supporting table 3 provided at an upper portion of a frame 4. Slide guides 7 are provided at left and right side of the arm 6 and a slider 9 is fitted within the guides slidably. The arm 6 may be pivotted by 360° and a cutter 1 is attached to the slider 9 so that the cutter 1 is intersecting parpendicularly with the center line 12 of the shaft 5 in its axis and passing through the center line 12 of the shaft 5 in its working surface. Accordingly the intersecting point of the moving trace 20 of the cutter 1 and the line 12 is constant, therefore, the setting of the cutter 1 and the line 12 is constant, therefore, the setting of the cutter in case the cutting angle thereof is changed becomes easy, and thereby, it is particularly effective for a production of small quantity in many varieties.