An electric power steering control device, comprising: - steering torque detection means for detecting a steering torque applied by a driver from a relative angle of a torsion bar; - a torque controller for computing an assist torque current for assisting the steering torque based on a steering torque signal detected by the steering torque detection means; - a motor for generating a torque for assisting the steering torque; - rotation speed estimation means (4, 5) for estimating a rotation speed of the motor; and - a damping controller for computing a damping current to be added to the assist torque current by using an estimated value of the estimated rotation speed of the motor, - wherein the rotation speed estimation means (4, 5) include: -- steering component removing means for steering torque, for removing a component due to steering from an output of the steering torque detection means; characterized in that -- a rotation angle corresponding value computing means for multiplying an output of the steering component removing means for steering torque by an inverse number of a rigidity of the torsion bar and -1 to compute a value corresponding to a rotation angle; and -- a rotation angle differentiator for differentiating an output of the rotation angle corresponding value computing means to compute a value corresponding to a rotation angular velocity. - steering torque detection means for detecting a steering torque applied by a driver from a relative angle of a torsion bar; - a torque controller for computing an assist torque current for assisting the steering torque based on a steering torque signal detected by the steering torque detection means; - a motor for generating a torque for assisting the steering torque; - rotation speed estimation means (4, 5) for estimating a rotation speed of the motor; and - a damping controller for computing a damping current to be added to the assist torque current by using an estimated value of the estimated rotation speed of the motor, - wherein the rotation speed estimation means (4, 5) include: -- steering component removing means for steering torque, for removing a component due to steering from an output of the steering torque detection means; characterized in that -- a rotation angle corresponding value computing means for multiplying an output of the steering component removing means for steering torque by an inverse number of a rigidity of the torsion bar and -1 to compute a value corresponding to a rotation angle; and -- a rotation angle differentiator for differentiating an output of the rotation angle corresponding value computing means to compute a value corresponding to a rotation angular velocity. -- steering component removing means for steering torque, for removing a component due to steering from an output of the steering torque detection means; characterized in that -- a rotation angle corresponding value computing means for multiplying an output of the steering component removing means for steering torque by an inverse number of a rigidity of the torsion bar and -1 to compute a value corresponding to a rotation angle; and -- a rotation angle differentiator for differentiating an output of the rotation angle corresponding value computing means to compute a value corresponding to a rotation angular velocity. -- a rotation angle corresponding value computing means for multiplying an output of the steering component removing means for steering torque by an inverse number of a rigidity of the torsion bar and -1 to compute a value corresponding to a rotation angle; and -- a rotation angle differentiator for differentiating an output of the rotation angle corresponding value computing means to compute a value corresponding to a rotation angular velocity.