To prevent a pinhole from being formed in a joint part when a fluctuation exists in a polishing quantity of respective cutting edges when a finger joint is formed by cutting them as finger cutters by layering repolished unit finger cutters.

A surface plate 14 having a reference bar coming into contact with a flank relief of an edge part and a cutter installing shaft where a nut 17 is screw-fitted to and installed in its center, are installed on base board members 11 and 12 which can be positioned on a table of a tool grinder. A sleeve having a collar installed by layering unit cutters 1 is fitted to and installed on a cutter installing shaft, and a sleeve cap 19 is fitted and installed so as to press down the unit cutters, and a notch spacer 22 is inserted between it and the nut 17, and is loosely fastened by the nut 17. The flank of the edge part of the cutters are uniformly brought into contact with the reference bar, and when a cutting face formed in parallel to a table sending surface is polished by a grinding wheel, stable accuracy is obtained.