Abstract: An automatic door opening and closing system opens a door by driving means when a person approaches the door. A monitoring area is set in the vicinity of the door, and moving speed and direction computing means computes the speed and direction of movement of the person on the basis of changes in position of the person in the monitoring area. When it is judged from the computed direction of movement that the person is moving toward the door, door enabling area selecting means selects one of plural door enabling areas suitable for the speed of movement of the object. Open-door command means provides an open-door signal, which causes the door to be opened at a fixed speed, to the driving means so that the door is fully opened upon the predicted arrival of the person at the door.