A rotary electric device control device for controlling driving of a rotary electric device including a plurality of winding sets, includes: a plurality of drive circuits; and a plurality of control units that include signal output units for outputting control signals to the drive circuits corresponding to the control units, respectively. The one of the control units generates a control signal according to a command value calculated by each system, a host system detection value relating to a detection value of a host system, and another system detection value relating to another detection value of another system. An electric power steering device includes: the rotary electric device control device; the rotary electric device that outputs an assist torque for assisting a steering operation of a steering wheel by a driver; and a power transmission unit that transmits a driving force of the rotary electric device to a drive target.