A cutting blade is fixed on a shaft that rotates about its shaft center, and that is linearly advanced by an advancing movement. The shaft's center further revolves with a small radius of revolution at a rapid predetermined rate of revolution greater than the rate of advancing movement. Thus the blade is pressed against and cuts a substrate and produces chips, and the blade is intermittently disengaged from the substrate whereby the chips move in the direction in which the blade rotates to be removed from between the cutting edge of the blade and the substrate. This reduces working resistance, enhances working efficiency, and prevents the blade surface from having significant frictional heat. Furthermore, the generated frictional heat can readily dissipate and the blade can thus have a long life.