This is a system that measures the flatness of the steel plates. It is installed at the product inspection line and entry line, and is used to measure the flatness of steel plates before the shipment, which can then be used to determine the quality of the products. Also, it measures the surface shape information such as height, wavelength or pitch, waveness, C-curve, curl, gutter and etc, and sends them to the higher system so that this information can be used as a quality control reference during manufacturing process. This system enables to determine pass/fail of the quality.