PURPOSE: To perform the cutting works according to the signals, by placing the thickness meter and the width meter at the output side of the last rolling machine of the rolling mill line and whereby detecting automatically the change point and end point of the thickness of the specific rolled materials.

CONSTITUTION: The processing unit 6 is placed along with the signal 5a at the output side of the rolling machine 2. The thickness signal 7a given by the thickness meter 7, the width signal 8a given by the width meter 8 and the temperature signal 9a given by the thermometer 9 are respectively input to the processing unit 6. The cutting point of the rolled materials 1 is judged and determined by the unit 6 and the cutting signal 6a is input to the cutting machine 10 and the cutting is performed. The end point is detected in the same manner and the signal is input to the cutting apparatus 10.