In an electronic commutated motor, ripple of driving torque is perfectly compensated into uniform torque by controlling stator current; therein mechanical 360.degree. angle of rotation of the rotor magnet is divided into e.g. 12 partitioned ranges (of 30.degree.), said compensation being made by repeatedly reading out the same compensation data for the 30.degree. range by utilizing an address counter which is reset at each beginning of said partitioned ranges.