PURPOSE: To prevent the occurrence of seizure of the upper and under surfaces of a printed wiring original plate and an increased life for a saw blade is provided and to execute cutting of a printed wiring original plate with high quality and precision, in cutting of the printed wiring original plate by means of a saw blade.

CONSTITUTION: By feeding a high speed rotating saw blade 1 in the direction of an arrow mark 6 with the aid of a drive device 3 fixed on a moving base 5, a printed wiring original plate 2 is cut. During cutting of the original plate, a cutting work is executed in a state that two flows 9 and 10 of cooling air are blown against the upper and lower cut portions 13 and 14 of the printed wiring original plate 2 through nozzles 7 and 8.