An electric power steering device includes a torque detector including an input shaft rotational angle detector and an output shaft rotational angle detector configured to respectively detect rotational angles of an input shaft and an output shaft coupled by a torsion bar arranged in a steering system of a vehicle; an electric motor configured to be controlled based on a torque detection value detected by the torque detector, and to generate a steering assistance force to be exerted on the output shaft; a motor rotational angle detector configured to detect a motor rotational angle of the electric motor; and a noise suppression unit configured to reduce a noise in a signal of the rotational angle of the output shaft detected by the output shaft rotational angle detector, by using the motor rotational angle detected by the motor rotational angle detector.