The controller in an electric power steering apparatus stores the
relationship between the steering torque and the basic assist torque in
which the relationship is stored as assist characteristic, and stores the
relationship between the steering angle correspondence value
corresponding to the steering angle of the vehicle and the motor output
correction value in which the relationship is stored as correction
characteristic. The controller corrects the output of the motor, which is
required in order to generate the basic assist torque, in accordance with
the motor output correction value determined from the steering angle
correspondence value and correction characteristic, in which the basic
assist torque is determined from the steering torque and assist
characteristic. The correction characteristic is set so that the
denominator in the frequency transfer function
(K.sub.1.theta..sub.p+K.sub.2.theta..sub.ps+K.sub.3.theta..sub.ps.sup.2)/-
(s.sup.2/.omega..sub.0 .sup.2+2.zeta..sub.0s/.omega..sub.0+1) of the motor
output correction value to the steering angle correspondence value has a
term which includes the resonance angular frequency of the yaw motion of
the vehicle, and a term which includes the damping ratio of the yaw
motion of the vehicle.