PURPOSE: To enable the adjustment of lighting and line of sight by introducing an atmosphere from the outside.

CONSTITUTION: A pleat screen 1 for a vertical blind has a pleat screen S hung and supported through a runner R in a head box 6. The screen S is made up of a slat 2 and a lace 4. The slat 2 is made unable to see through. One side end of the lace 4 is bonded with an adhesive at one side end extending along the length thereof on one side of the slat 2 along the longitudinal direction. The other side end of the lace 4 is bonded with an adhesive at the other end of the slat 2 adjacent to the slat 2. With a distance maximized between the slats 2 adjacent to each other, the lace 4 is kept slackened. The lace 4 is also kept slackened with one end of the adjacent slats 2 in proximity to each other.