In determining a starting point of a motor of an electric actuator during its initialization procedure, when a rotation angle sensor detects pulse signals in a certain initialization pattern, power supply to the motor is stopped by the control of a motor drive circuit. This electrical control of motor rotation enables the initialization procedure of the actuator to be carried out without using mechanical restriction means for locking purposes, and the influence of variations in the deflection amount of any stoppers is eliminated. The precision in determining the starting point in the initialization procedure is thus improved.