PURPOSE: To contrive to improve a descaling property of a strip edge part and to prevent a local wear of a rolling roll by reduction rolling an central part in a width direction of a steel strip with a specified rolling reduction harder than an edge part to reduce a crown.

CONSTITUTION: A hot rolling steel strip 1 is subjected to rolling reduction by rolling reduction of 0.2W10% through a rolling mill 2, descaled from the surface of the steel strip 1 is a pickling vessel 3, then taken up as a descaled steel strip 4. In the stage of the rolling reduction, because the middle part in the width direction of the steel strip 1 is subjected to rolling reduction harder than the edge part to reduce the crown, a crown controller 5 is provided. On the inlet side of the rolling mill 2 or the outlet side or both the sides of the pickling vessel 3, a scale thickness meter 6 is provided to input a detected signal to the crown controller 5. The control device 5 controls the rolling mill 2 based on a set value and the detected value. As a result, the tensile stress is generated on the edge part, the cracks are generated on the relatively thick scale of the edge part, the descaling at the pickling on the succeeding stage is easily performed.