A signal generating section includes a second calculating section that corrects phase resistance. The calculating section stores resistance values of phases that have been measured in advance and a reference resistance value. The calculating section calculates correction components, which cancel a voltage drop term of a voltage equation of a d-q coordinate system changing depending on the rotation angle of the motor, based on the stored resistance values and the reference resistance value. The signal generating section superimposes the correction component and the correction component on a d-axis voltage command value and a q-axis voltage command value, respectively. The d-axis voltage command value and the q-axis voltage command value are thus corrected in such a manner as to suppress a torque ripple caused by difference among the resistance values of the phases.