PURPOSE: To spread water on neither upper surface nor lower surface of a steel plate irrespective of injection of water to both upper and lower surfaces of the steel plate by arranging a pair of a caliber work roll on the lower side and a flat work roll on the upper side at the final stand of a finishing mill and forming checkered projections on the surface of the lower side of the steel plate.

CONSTITUTION: At the final stand of the finishing mill, the steel plate 4 is rolled down by a pair of an upper flat work roll 1 and a lower caliber work roll 2 to form reticulate projections on the lower surface. Then, on the outlet side of the finishing mill 6, water is injected by runout sprays 5 on both upper and lower surfaces of the moving steel plate 4. After finish rolling is completed, water droplets hardly remain on the surface of the flat upper side of the steel plate 4 and water hardly spreads. Further, water droplets hardly remain even on the surface of the lower side of the steel plate where projections are formed and water hardly spreads.