PURPOSE: To accurately perform a plate thickness and shape control by measuring a plate thickness in the plate width direction before and after shifting at the time of changing a shift value of a work roll shifting mill and assuming profiles of an upper and lower work rolls independently.

CONSTITUTION: The upper and lower work rolls 1, 2 are shifted relatively by a distance S1 devided at an equal interval, and a point B1 on the lower work roll 2 is allowed to coincide with a reference point A1 on the work roll 1. In this state, the plate thicknesses of points A1 and A3 on the roll 1 (points B1 and B2 on the work roll 2) are measured, and the differences between the measured plate thicknesses and calculated plate thicknesses are acquired, then the sum total of the upper and lower work roll profiles at points A2 and A3 are obtained. The value of the lower work roll profile at the point B1 on the lower roll 2 and the value of the upper work roll profile at the point A3 on the upper roll 1 are obtained respectively. In this way, the value of the upper work roll profile at the point A1 on the upper roll 1 and the value of the lower work roll profile at the point B3 on the lower roll 2 are obtained.