PURPOSE: To prevent creasing by ripple waving phenomena and to improve the yield of rolling in superposing aluminum foils and rolling the same by humidifying the inlet side foils just prior to rolling then rolling these.

CONSTITUTION: The aluminum foils A let off from a pair of payoff reels 1, 2 are wound and superposed respectively by deflector rolls 3, 4. The rolls 3, 4 are kept humidified in accordance with the thicknesses of the aluminum foils, room temp., the speeds of the aluminum foils, etc., and the aluminum foils superposed by the rolls 3, 4 are humidified to a required temp. These aluminum foils are fed via bridle rolls 5 to a rolling mill 6, by which they are rolled.