To give an auxiliary torque based upon the driver's will of steering with good followup performance, establish excellent performance of removing the turbulence, and presume the target value of control properly.

A motor-driven power steering device is structured so that the steering wheel torque TH of a driver applied to a steering wheel 3 is transmitted to the steered wheels W via a steering system 2 and the auxiliary torque Ta generated by a motor 8 controlled by a controlling means 12 is applied to the steering system 2, wherein a steering torque sensor TS is installed on the way of the steering system 2 for sensing the steering torque T, while the controlling means 12 decides the auxiliary torque Ta from the sum of the feedforward term based upon the steering wheel torque and the feedback term based upon the deviation of the steering wheel torque from the steering torque. The steering wheel torque TH is presumed from the steering torque T. The term based upon the deviation of the motor rotating speed from the steering wheel rotating speed is added to the feedback term.