To operate a loom by an optimum number of revolution in which stability and productivity of woven fabric in weft inserting is taken into consideration.

In this fuzzy controller, running state of weft is detected and corrected amount of number of revolution of a motor is obtained by fuzzy reasoning based on the detected value, driving the motor by a prescribed number of revolution and correcting number of revolution of the motor based on the corrected amount. Further, corrected value of pressure of a fluid for wefting fed to wefting nozzle is obtained by fuzzy reasoning based on the detected value and further, wefting fluid is fed to a wefting nozzle under prescribed pressure and pressure of wefting fluid is corrected based on corrected amount of the pressure.