PURPOSE: To elevate the giant slalom performance of a ski board so as to shorten the sliding time of the giant slalom by forming the rear end of a ski board into the shape of an equilaterlly triangular projection or recess, based on one side of the tail width of the ski board, and cutting a center groove at the tail thereby providing it with center edges.

CONSTITUTION: The rear end tail edge of a ski board is made in the shape of an equilaterally triangular projection or recess, whereby the giant resistance of a tail double-edge at the time of the sliding turn on snow sharpens, and the snow is swept out from an I-shaped or triangular groove, and the resistance becomes smaller than a conventional one. And, when the ski board is maintained aslant during giant slalom, the bite of the edge becomes large, and the rear tail floating sliding phenomena which enlarges the turning moment occurs.