To provide a control device of an electric power steering device, which correctly prevents the state in which a grip is lost by a steering operation even when a grip state of a tire is detected with high accuracy, and the rapid steering operation is performed.

A SAT computation value SATa generated based on the assist torque Tm or the like is computed. The SAT estimated value SATb actually generated based on the lateral force is estimated. The grip loss degree g is calculated from the computation value SATa of the self-aligning torque and the estimated value SATb. The torque correction value T is set, which is larger as the grip loss degree g is larger and as the angular velocity is larger from the grip loss degree g and the angular velocity of an electric motor 12 as the steering angular velocity equivalent value. The current command value Itv is corrected by subtracting the equivalent torque correction value T from the current command value Itv corresponding to the steering torque T and the vehicle speed V, and the electric motor 12 is driven based on the corrected current command value Itv as the steering assist command value Im.