In an electric power steering control system, a phase compensator of the steering torque is made of an analog circuit and an anti-phase compensator is made by the software of a microcomputer, thereby to eliminate the changes in the gain and the phase by the phase compensator of the analog circuit near the oscillation frequency, so that the steering torque signal equivalent to that of no phase compensation necessary for the computation at the observer is computed from the phase-compensated steering torque signal.