PURPOSE: To allow reduction of wow and flutter by suppressing fluctuation of torque caused by the structure of DC motor.

CONSTITUTION: A disturbance estimation unit 10 calculates an estimated value ΔT1 of torque T1 by multplying an armature current Ia flowing through an armature coil 2 by a nominal value of torque constant determined by a constant unit 11. The estimation unit 10 further calculates an estimated value ΔT2 of output torque T2 by multiplying the r.p.m. N of a load inertia 5 by a differentiation element 12. A disturbance torque estimated value ΔTdis is then calculated by subtracting the output torque estimated value ΔT from the torque estimated value ΔT1. ΔTdis is fed through a filter 14 to a coefficient unit 15 where an armature terminal voltage correction value Vb of disturbance torque Tdis is calculated. The correction value Vb is applied to the armature coil 2 and the armature current Ia is varied. The disturbance torque Tdis is suppressed by varying the torque T1 by an amount corresponding to the product of the variation of armature current and a torque constant Kt.