PURPOSE: To provide a device to put out mark string so that a ski board can be easily detected when the ski board has gone somewhere or gets under snow after it is slipped out of ski boots when a skier falls down in skiing at sliding time.

CONSTITUTION: (A) A vessel 1 fixed by a screw or the like is arranged on a ski board 8. (B) The end of mark string 2 of about 2 to 4m is fixed to an inside surface of the vessel 1. (C) The other end of the mark string 2 is fixed to a cap 3. (D) String 6 whose one end is fixed to the cap 3 and other end is tied with a Velcro tape 5 is arranged on an outside surface of the cap 3. (E) In the vessel 1 and the cap 3, recessed-projecting parts 4 by which the vessel 1 is closed by the cap 3 and the cap 3 is easily slipped out of the vessel 1 when the string 6 is pulled are arranged in corresponding parts of the vessel 1 and the cap 3.