PURPOSE: To reduce the fluctuation quantity of width in the stationary region of a metal plate by estimating the fluctuation quantity of width in the stationary region and changing the rolling reduction of roll at the final pass of forming rolling along the rolling direction of a material to be rolled based on this estimated fluctuation quantity of width.

CONSTITUTION: Forming rolling along the rolling direction of the material to be rolled and broadside rolling that the material to be rolled after forming rolling is turned by 90° to screw down in the widthwise direction are executed. The plane shape of the metal plate is finished into an approximately rectangular shape by combining finish rolling by which the material to be rolled is further turned by 90° after this broadside rolling is executed. The fluctuation quantity of width in the stationary region except the tip and rear end part of the metal plate is estimated and the rolling reduction of roll at the final pass of forming rolling is changed along the rolling direction of the material to be rolled based on this estimated fluctuation quantity. In this way, the fluctuation quantity of width in the stationary region of the metal plate after the completion of rolling can be decreased, crop loss is reduced and yield is still more improved.