PURPOSE: To perform reliable closing of a scrren by a method wherein first and second door stop pieces are mounted on the upper and lower end parts and the central part in a vertical direction of a rail on the screen stopper side of a screen and a slope end part on the indoor side is formed at the extension part of a second door stopper piece.

CONSTITUTION: A second door stopper piece 62 is arranged to a vertical rail 56 on the screen stopper side in a manner to be situated facing a position where a deformation amount of warp deformation produced at the vertical rail 56 on the screen stopper side of the screen 31. An extension part 66 is arranged to the second door stopper piece 62 and an end part 67a on the indoor side of a slope 67 of the piece 62 throughout the extension part 66. During closing of the screen 31, a guide size F, extending along an indoor and an outdoor direction, of the slope 67 of the second door stopper 62 to guide the vertical rail 56 on the screen stopper side to the indoor side is ensured to a high value and reliable closing of the screen 31 is ensured. The extension part 66 is served to prevent a part 56b of the vertical rail 56 on the screen stopper side from collision with a guide protrusion 28a of a right vertical rail 28. Further, contact of the slope 67 with the guide protrusion 28a causes reduction of the occurrence of the whole of the screen 31.