A controller for use with a motor including a stator, around which three-phase coils are wound, and a rotor, which includes a magnet functioning as a first magnetic pole and a salient pole of a core functioning as a second magnetic pole. The controller supplies the three-phase coils with excitation currents having a predetermined phase difference from one another to drive and rotate the rotor. The controller includes a current adjustment unit that adjusts a fundamental wave current using high-order currents for third order and ninth order components in a q-axis to reduce torque ripple. The excitation current is generated based on the fundamental wave current adjusted by the current adjustment unit.