To provide a flat curtain which may be divided into the plurality and interlocked with one rail in which a plurality of curtain rails are connected each other so that the curtains may be interlocked and so that the curtains before and behind are not crossed each other.

The width of a curtain rail 28 may be set at the necessary one by using a rail wall 5 and a width controlling plate 6, the width of a runner 1 and the attachment position of a curtain 13 may be set with shifting by a runner width plate 3, a roller runner 2 and a attaching tool 4, a plurality of curtains may be divided and interlocked before and behind by combining a curtain attaching stand 10 in which a guide rail 11 and a guide 12 are placed before and behind and a guideline 17 for the lower part in which a lower part weight 16 is placed so that the curtains are not crossed each other and a guide liner 18 for the lower part through which it passes are placed.