Abstract: A locking device for cords of a sun-blind or the like having an upper beam and one or more webs of sun-blinding material connected thereto. The cords extend through the internal space of the upper beam and leave it for opening or closing the sun-blind. The locking device consists of a U-shaped portion in the legs of which a tumbler is pivotably supported at the one end. The free end of the tumbler is biased in the direction of the bottom of the U-shaped portion. The cords extend between the free end of the tumbler and the bottom of the U-shaped portion and are locked when they are clamped between said free end and bottom resulting from the bias force.