There are provided a composition for forming a superfine pattern and a method employing the same for forming a superfine pattern. The composition enables to simply produce a superfine pattern with high mass productivity.The composition comprises perhydropolysilazane (I), silicon-containing polymer (II) having a hydrocarbon group, and a solvent. The mixture of those polymers contains silicon-hydrogen bonds and silicon-hydrocarbon group bonds in such amounts that the number of the silicon-hydrocarbon group bonds is in a ratio of 1 to 44% based on the total number of the silicon-hydrogen bonds and the silicon-hydrocarbon group bonds. The composition is applied on a resist pattern to form a spacer formed of the composition on the side wall of the ridges in the pattern, and then the spacer or a resin layer disposed around the spacer is used as a mask to form a superfine pattern.