To precisely perform polishing of a cutting edge of a drill by accurately performing centering of the drill.

A drill 2 is centered by bringing the tip of a spiral-shaped drill groove of the drill 2 in contact with a centering claw 15 of a centering tool 3, the centered drill 2 is chucked by drill chucks 4 of a drill polishing machine 1, and a cutting edge 5 to be polished on the tip of the drill 2 is brought in contact with polishing surfaces 8, 9 of grinders 6, 7 and precisely polished. A plurality of centering parts 13 corresponding to the drill diameter are arranged on the centering tool 3 to the diameter of the drill to be positioned, and a drill 2 to be polished and having the different diameter is easily centered by the centering parts 13 corresponding to the drill diameter and can be polished.