The present invention relates to a tensioning device. And more specifically, the provided tensioning device resolves a problem of cancelling tension from a wire by arranging a plurality of rollers installed at a fixated pulley and a transfer pulley in a line, and to stably operate a roll screen vertically. The present invention comprises: a rail formed lengthily with an inner space; a fixated portion on which a roller coupling hole is formed on the lower surface of a support portion; a guide roller installed to guide the wire to the roller coupling hole of the support portion; the fixated pulley connected to a connection projection of the fixated portion; a moving portion installed symmetrically with the fixated pulley; the transfer pulley connected to the connection projection of the moving portion; the wire supplied to the outside through the guide roller of the fixated portion; an elastic spring having a loop in the either side; and a tension controlling portion formed with a connection hole and formed with an end sill with a washer connection hole.
