PURPOSE: To operate an obstacle sensing mechanism safely and surely using a simple structure without including a driving power source for driving the obstacle sensing mechanism on the side of a shutter curtain.

CONSTITUTION: An obstacle sensing mechanism 19 for sensing an obstacle in the whole area in the width direction of an opening is attached to the winding- start edge of shutter curtains 5a, 5b, 5c, and a sensing signal output wire 15 of the mechanism 19 is incorporated into each suspension cord body. And a sensing, non-sensing state of the mechanism 19 is transmitted to a driving controller of a winding drum 10 through the suspension cord body.