PURPOSE: To permit even a hard material to be efficiently cut through friction by allowing the outer periphery of a light metal disc in high speed revolution to be pressed onto the material to be worked.

CONSTITUTION: A material to be worked is fixed on a table 7 and a metal disc 13 is revolved at about 2,000W4,000rpm. Then, an actuator 17 is extended and an arm 11 is turned to the direction of arrow R, the metal disc 13 is pressed onto the material to be worked. The material to be worked is locally heated through friction between the material and the metal disc, and changes to the semi-molton or fused state, and the hardness is reduced. When the metal disc 13 is pressd onto the material to be worked in this state, the disc 13 bites into the semi-molten or fused part, and the article to be worked is cut by the metal disc 13.