In order to solve a problem that a motor generates a noise so as to deteriorate an environment in a vehicle if a field weakening control is executed to the motor of a electric power steering apparatus, in the case that a vehicle speed is high, the same field weakening control as the conventional one is applied to the motor because a noise generated due to a friction between a tire and a road surface and a wind noise of a vehicle body are large, and in the case that the vehicle speed is low, the field weakening control is weakly applied in comparison with the conventional one because the noise generated by the motor is felt relatively largely. Accordingly, the field weakening control can be executed in response to the vehicle speed in such a manner as to make the motor noise smaller.