An electric power steering device of a steer-by-wire type includes: 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 is prevented from being 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. At least one of the steering motor or the reaction force motor is constructed of a double-winding motor of a double-inverter type in which each of windings is duplexed, and the respective duplexed windings are individually driven by two inverters.