To restrain increase of winding diameter of side edge parts and prevent a fray from generating by executing cutting provided with cutout on the side edges of the screen of a roll blind to form fray preventing parts, and lock sewing and melting the thread.

A screen 5 is hung down from the winding shaft 4 of a roll blind 1, and a weight bar 6 is hangingly supported with the lower end of the screen 5. Both side edges of the screen 5 made of woven cloth are cut into wave-like, oblique, zigzag, or the like form to form cutouts. Lock sewing is executed on the side edges with transparent thread of low melting point polyester, and the sewn part is heated to melt sewing thread and form fray prevention parts 8a, 8b. Because the fray prevention parts 8a, 8b are zigzag cut, the sewing thread is melted, difference of thickness between them and the center part of the screen 5 is small, and a fray can be surely prevented from generating.