Abstract: The invention matches the material quality of a product to target data, even when a materials quality model is insufficient in prediction accuracy. Heating a metallic material, rolling, forging, or leveling the metallic material, and cooling the metallic material are each conducted at least once. Prior to manufacture of a metallic product of a desired size and shape, qualitative data of the metallic material are measured at a position by materials, quality sensor in a manufacturing line, and modifications based on measured data are made to heating, processing, or cooling conditions in at least one of the steps, upstream of the materials measured data sensor so that the quality of the metallic material at the measuring position agrees with target data.