To provide a method for easily applying DLC coating 36 to a side surface 34 of an edge 32 part of a cutting tool 30 so as not to generate a burr 24 even if cutting work is performed on soft metal 10.

This purpose can be attained by applying the DLC coating 36 to the cutting tool 30 after covering the whole edge 32 of the cutting tool 30 in the DLC coating method to the cutting tool 30. The DLC coating 36 is an abbreviation of "diamond like carbon", and is an amorphous carbon film mainly composed of carbon and hydrogen, and is close to diamond in hardness.