PURPOSE: To easily estimate a quantity of expansion, a quantity of wear by measuring a difference load in a zero checking time for rolling down and leveling after work rolls are recombined, storing it as an initial value, reproducing a kiss roll state at a zero checking time in an idle time and calculating a roll profile through a difference between the difference load and the initial value at that time.

CONSTITUTION: The difference load at the zero checking time for the rolling down and leveling is measured after the work rolls are recombined in a hot finishing rolling mill 1 and this is stored as the initial value. The kiss roll state at the zero checking time is reproduced in the idle time after an arbitrary number of sheets are rolled, the difference load at that time is measured and stored and further a roll profile change in the width direction is calculated by a difference from the previously stored initial value. In this way, the roll profiles on the work side WS and the drive side DS in a rolling time can be detected without using a special measuring apparatus and the thickness, crown and shape of a rolled sheet can be improved in accuracy.