PURPOSE: To output a load rate reference signal capable of preventing the breakage of paper to each motor by inputting the electric current values of a main roll-driving motor and an auxiliary roll-driving motor and the control style and the load-bearing set value for the auxiliary roll into a load rate reference-calculating circuit.

CONSTITUTION: An information-judging circuit 19 judges the control style of an auxiliary roll 1 from the width dimension, weight and water content of paper, the concentration and temperature of a coating solution and the pressing force of a main roll 5, and inputs a control switch signal 20. A load rate reference-calculating circuit 21 calculates load rate references iRB, iRT from the electric current values iT, iB of motors 2, 6, the control switch signal 20 and a load bearing rate set value IR from a load bearing-setting device 22, and outputs the calculated load rate references iRB, iRT to a main driving device 8 and an auxiliary driving device 4. The breakage of paper caused by switching the control of the auxiliary roll and the breakage of the paper when the paper is sized, pressed and coated can be prevented.