To improve the accuracy of tension control without damaging the stability of a looper angle.

The angular deviation between the deteced value θ of a looper angle and the target value θREF is inputted and a descriminated result about whether this angular deviation is within a prescribed allowable range or not is outputted to a gain switching means 16 with an angular deviation discriminating means 15. Based on this discriminated result, when the angular deviation is within the allowable range, the angular deviation smaller than the inputted angular deviation is outputted to an integral compensator 14. In this way, integral compensation is executed by giving weight to making the tension deviation zero than making the deviation of the looper angle zero with the integral compensator 14. And, when the angular deviation is out of the allowable range, the output value equal to the inputted angular deviation is outputted with the gain switching means 16.