To provide a method of polishing the blade edge of a cutter for cutting a work with a stable machining accuracy in a stabler wear area by producing the same state as that provided after worn by the machining of the work by allowing the blade tip to be worm beforehand.

In an unused cutting tool 1, a blade edge 2 is polished until the state of an initial wear amount becomes a worn state beforehand by the polishing part 5 of a grinding wheel 3 attached to the chuck 11 of the rotating shaft 10 of a lathe. By this, the occurrence of defective parts by the machining of the works formed of a steel based cut material to the degree that the initial wear amount is worn can be avoided, and the works can be machined by using a polished cutting tool with the working accuracies such as a high dimensional accuracy and a high surface roughness from the first time.