To provide a controller of rotary electric machine which can control voltage of each set of the winding appropriately within a range less than or equal to the DC power voltage, to the rotary electric machine which has plural sets of windings. A controller of rotary electric machine calculates, for each set, a required DC voltage which is a minimum DC power voltage required for applying a voltage according to the voltage command value to the winding, based on the voltage command value; calculates one common required DC voltage which is common to all sets, based on all sets of the required DC voltages; changes the common voltage control value so that the common required DC voltage-approaches the DC power voltage; and changes each set of the current command value based on the common voltage control value.