In a case where a computing period of a torque ripple compensation section which computes current compensation values Δid and Δiq to be caused to flow into a motor in order to prevent occurrence of a torque ripple in the motor differs from a control period of a current control section which controls a feedback to the motor in such a way that current command values i*d and i*q additionally provided with the current compensation values Δid and Δiq flow into the motor, the microcomputer sets the current compensation values Δid and Δiq to zero when a rotor angular velocity ωre of the motor is equal to or greater than a first threshold value ω1.