To prevent skidding by a method wherein the undersurface of a board is so formed to be convex across the length thereof and edges are formed sticking on both side rims of the undersurface of the board to accomplish an edging operation simply while improving linearly gliding performance.

The undersurface of a board 1 with a top part 11 thereof warped is so formed to be convex across the width thereof excluding the top part 11 thereof. Moreover, edges 12 are formed sticking on both side rims occupying the most part of a gliding surface on the undersurface of the board 1. As the board 1 has a convex undersurface and sticking edges 12, as compared with the board having a flat surface, glidability and straight running performance are improved thereby eliminating accidental skidding. The edges 12 can work easily by a slight shifting of the physical weight thereby enabling handling of the board simply in turning, traversing and the like.