An electric power steering device of a steer-by-wire type, comprising: a steering input mechanism , which includes a steering wheel to be operated by a driver; a reaction force motor , which is configured to apply a steering reaction force to the steering wheel; a steering motor , which is configured to output a steering force; a steering mechanism , which cannot be mechanically connected to the steering input mechanism, and is configured to steer a steered wheel through the steering force generated by the steering motor; and a drive control device , which is configured to carry out drive control for the steering motor and the reaction force motor, characterized in that at least the reaction force motor is constructed of a double-winding motor of a double-inverter type in which each of two windings is individually driven by one of the two inverters, wherein, when the double-winding motor of the double-inverter type fails, the drive control device is configured to control, in accordance with a drive current detected in a failed system out of two systems of the windings of the double-winding motor, a drive current to a winding of the failed system and to a winding of a non-failed system, or, in a case where another motor is provided together, a winding of the another motor provided together, wherein the drive current to the winding of the non-failed system, or to the winding of the another motor provided together, is increased by an amount for supplementing the decreased output of the failed system, wherein the double-winding motor of the double-inverter type comprises a three-phase double-winding motor of the double-inverter type including two sets of three-phase windings and two inverters configured to individually drive the respective two sets of the three-phase windings. a steering input mechanism , which includes a steering wheel to be operated by a driver; a reaction force motor , which is configured to apply a steering reaction force to the steering wheel; a steering motor , which is configured to output a steering force; a steering mechanism , which cannot be mechanically connected to the steering input mechanism, and is configured to steer a steered wheel through the steering force generated by the steering motor; and a drive control device , which is configured to carry out drive control for the steering motor and the reaction force motor, characterized in that at least the reaction force motor is constructed of a double-winding motor of a double-inverter type in which each of two windings is individually driven by one of the two inverters, wherein, when the double-winding motor of the double-inverter type fails, the drive control device is configured to control, in accordance with a drive current detected in a failed system out of two systems of the windings of the double-winding motor, a drive current to a winding of the failed system and to a winding of a non-failed system, or, in a case where another motor is provided together, a winding of the another motor provided together, wherein the drive current to the winding of the non-failed system, or to the winding of the another motor provided together, is increased by an amount for supplementing the decreased output of the failed system, wherein the double-winding motor of the double-inverter type comprises a three-phase double-winding motor of the double-inverter type including two sets of three-phase windings and two inverters configured to individually drive the respective two sets of the three-phase windings. <EOS>