To make it possible for a ski to catch well the extremely fastened face of snow made by a snow machine which is seen recently in many skiing grounds and pressed to prevent melting and to slide smoothly.

To deal with hard snow, a functioning part of a supplemental edge is shortened by mounting short functioning parts on the bottom end of the supplemental edge leaving spaces to reduce catching effect to the snow surface as shown on the illustration. This, at the same time, makes it possible to maintain stability because of a way of mounting to leave spaces which enables the functioning parts to be brought into contact with the snow surface even if it is bumpy. Then, the functioning parts of the supplemental edge onward directed and outer slanted part 3 is thinned to be sharpened like a pointed knife blade to reduce friction between functioning parts 2 of a sliding supplemental edge and the snow surface. The onward directed and outer slanted part 3 is made to have an obtuse angle to the snow surface to reduce friction, and its backward directed part is made shaped like a scraping 4 to produce braking effect when a ski itself is sided against the snow surface to do edging.