Abstract: A manually and automatically operable curtain is provided with an electric motor, a planetary gearing of which the sun gear is fixed to the output shaft of the motor, a driven gear engageable with the planet gear of the planetary gearing, a cord pulley fixed to the driven gear for drawing the curtain, and an electric control system including a motor-reversing device. The rotation of the motor is transmitted to the cord pulley through the intermediary of the planet gear when the motor turns. Responsive to a signal to stop the motor, the motor-reversing device reverses the motor for a very small time so as to disengage the planet gear from the driven gear. Thus, the curtain is easily operated by hand without receiving the rotational resistance of the motor.