PURPOSE: To produce smooth product with no burrs on its cut part by cutting the material along its groove as applying strong twist force on the material.

CONSTITUTION: The material 21, fixed in a chuck e, is grooved to form a groove 22 by grooving roller f. Next, the product 23 is held at the fixed chuck g set opposite to the chuck e against the groove 22, which give a strong twist force to the said material 21 fixed in the rotating chuck e, thus the product 23 is cut to be separated from the material 21 at the groove 22. The cutting in this manner guarantees the production of the product 23 with no burrs bents on a cut surface, convex etc., not harming the material shape.