PURPOSE: To improve the wear resistance and realize the super-finish of a work in a stable manner by fixing a thin section of a super wear resistant material to at least a part of the inner wall surface of a square groove or square hole to accommodate a grinding stone.

CONSTITUTION: A holder for a grinding stone accommodates a rectangular solid super-finish grinding stone in a square groove 12, mounts a lid B on the upper surface thereof, and holds the grinding stone. The square groove 12 is worked at the center of the rectangular super-hard material in the body A, and the polycrystal diamond sintered body 11 formed to the prescribed shape is fixed by brazing to each end of the rectangle. In the lid B, a thin strip of the polycrystal diamond sintered body whose size is matched to the width of the groove of the body A is fixed with the adhesive at the center of the rectangular plate opposite to the body A. The body A consists of a body part 13 and the super wear-resistant material 11, and the body part 13 is made by grinding the super hard material to the prescribed dimensions by the diamond grinding wheel. On the other hand, the polycrystal diamond sintered body 11 is cut out of the diamond compact material to the prescribed dimensions by the wire electrical discharge machining to form a thin section 16.