In a vacuum chamber, the edge of each blade group is subjected to an ion beam treatment under predetermined conditions using a plasma ion gun and argon as a medium, and is subjected to a plasma ion implantation of nitrogen plasma under predetermined conditions using a plasma ion implantation gun. As a result, it is possible to provide a blade member having an edge of a cutting quality enhanced by increasing the sharpness, a blade member having an edge of a rigidity enhanced by increasing the hardness, and a working apparatus capable of working those edges efficiently.