Abstract: A slide door is provided to be movable between a closed position to cover a side opening formed at a vehicle-body side face and an open position. The slide door is configured to move outward and subsequently slide rearward along a rear vehicle-body outer face when the slide door moves from the closed position to the open position. There is provided a detection sensor to detect a foreign matter in coming into a gap from a vehicle-compartment inside. A drive of the slide door is stopped in case the detection sensor detects the foreign matter in coming into the gap when the slide door moves toward the open position. Thereby, any foreign matter can be prevented from being pinched in the gap formed between the slide door and the rear edge portion of the side opening.