PURPOSE: To perform highly accurate flux operation and to realize highly accurate flux operation type vector control over the entire speed region by employing a value obtained from a voltage command applied to a power converter in place of the motor terminal voltage necessary for flux operation in a low speed region including starting region of an induction motor.

CONSTITUTION: An induction motor controller comprises a voltage operating means 24 for operating the actual voltage value of each phase based on a voltage command fed to a power converter 2 and a switching means 21 for leading a voltage value calculated through a voltage operating means 24 to the flux operating means 11 under low speed region and being switched to lead the actual voltage value of an induction motor 3 under high speed region. Actual primary voltage is employed as the input voltage value for flux operation under high speed region while a voltage command value being fed from a controller 10 to the power converter is employed in place of the actual primary voltage under low speed region. By such arrangement, flux operation is performed highly accurately over the entire speed region and flux operation type vector control can be carried out highly accurately over the entire speed region.