A method of forming a pattern including applying a resist composition to a substrate to form a resist film, and then subjecting the resist film to exposure and development, thereby forming a first pattern containing a resist film; forming a SiO2 film on the surface of the first pattern and the substrate; subjecting the SiO2 to etching such that the SiO2 film remains only on a side wall portion of the first pattern; and removing the first pattern, thereby forming a second pattern containing the SiO2 film. The resist composition contains a base component that exhibits changed solubility in a developing solution under action of an acid, and an acid generator component that generates acid upon exposure, the base component containing a resin component containing a structural unit having an acid decomposable group which exhibits increased polarity by the action of acid and has no polycyclic group.