PURPOSE: To measure the rolling load during rolling and also to measure not only the rolling load in the rolling-down direction but also the tension between stands.

CONSTITUTION: One roll shaft 6, at least, among three roll shafts is non-rotational and supported through bearings 14 between a roll 3 and the shaft 6. Rolling-down directional strain gages 20, 21 installed on a pass line side and an opposite pass line side of the rolling-down direction of the non-rotational roll shaft 6 and tensile direction strain gages 22, 23 between stands installed on a pass line inlet side and a pass line outlet side are provided. Further, the device is composed of a rolling load arithmetic part 32 to calculate the rolling load of the rolling-down direction and the tension between stands of roll shaft based on the bending strain in the rolling-down direction of the roll shaft 6 inputted from the rolling-down directional strain gages 20, 21, the bending strain of the pass line direction inputted from the strain gages 22, 23 of the direction of tension between stands, the relation of the bending strain and the rolling load of rolling-down direction of the roll shaft 6 preliminarily inputted and being set, and the arithmetic equation from the bending strain of the pass line direction.