A pattern is formed by coating a resist composition comprising a polymer comprising recurring units having an optionally acid labile group-substituted naphthol group, an acid generator, and an organic solvent onto a substrate, baking to form a resist film, exposing the resist film to high-energy radiation, baking, and developing the exposed film with an organic solvent developer to form a negative pattern wherein the unexposed region of film is dissolved and the exposed region of film is not dissolved. In the process of image formation via positive/negative reversal by organic solvent development, the resist film has a high dissolution contrast and controlled acid diffusion. By subjecting the resist film to exposure through a mask having a lattice-like pattern and organic solvent development, a fine hole pattern can be formed at a high precision of dimensional control.