A control apparatus (10) for controlling a three-phase rotary machine (80) having two three-phase winding sets (801, 802) includes: two power converters (601, 602) outputting AC currents, having a same amplitude and a phase difference of (30±60×n) [deg], to the two winding sets; a harmonic component generator (20) superimposing a harmonic component on a phase current first harmonic component of a current command value; and two controllers (331, 332) calculating voltage command values for the two power converters according to the current command value. A combination of amplitudes of the phase current fifth and seventh harmonic components to reduce a peak of the phase current first harmonic component is defined as a fundamental amplitude. The harmonic component generator performs a harmonic amplitude reduction process to reduce a phase current peak reduction amount of the phase current first harmonic component from the fundamental amplitude according to a predetermined parameter, and to reduce an absolute value of an amplitude of the harmonic component.