PURPOSE: To obtain an induction motor controller which has high resistance to the secondary resistance changes caused by the magnetic saturation due to the load fluctuation, the variance of the rotational speed, or the temperature change and can obtain a prescribed torque.

CONSTITUTION: The computing elements 49, 43 and 44 calculate an actual magnetic flux or an actual torque current, or the changing rates of the actual magnetic flux and a secondary magnetic flux command of an induction motor 2 based on the voltage or the current of the motor 2, or a signal equivalent to the voltage or the current. The comparators 45, 46 and 47 compare the secondary magnetic flux command with the actual magnetic flux, s torque command with the actual torque current, and the changing rate of the actual magnetic flux with the changing rate of the secondary magnetic flux command respectively. Then the mutual inductance and the secondary resistance which are preset at a magnetizing current computing element 28 and a slip frequency computing element 36 are corrected through a fuzzy logic 48. So that the deviation of each comparison is satisfactorily reduced.