PURPOSE: To smoothly open a door when electric power is supplied again by controlling a door motor on the basis of the opening pattern data of a memory means which corresponds to the standard positions of the perfect closure position, non-brake position, brake position, and the perfect opening position which a detector detects.

CONSTITUTION: A controller 29 inputs four standard position signals consisting of the perfect closure position, non-brake position, brake position, and the perfect opening position of a door which a standard position detector 15 detects, through the combination of two-bit signals. When electric power is supplied again on the restoration after service interruption of a power source circuit 26, the opening pattern data corresponding to the detected standard position is read out from a RAM 34, and a door motor 7 is driven through a PWM circuit 35, gate signal generating circuit 27, and a driving circuit 25 on the basis of the data, and the opening speed is feedback-controlled by the signals of an encoder 8 and a pulse counter 32. Thus, the door can be smoothly opened when electric power is supplied again.