A negative pattern is formed by applying a resist composition onto a substrate, exposing the resist film, and developing the exposed resist film in an organic solvent developer. The process further involves coating the negative pattern with a shrink agent solution of a polymer comprising recurring units capable of forming lactam under the action of acid in a C7-C16 ester or C7-C16 ketone solvent, baking the coating, and removing the excessive shrink agent via organic solvent development for thereby shrinking the size of spaces in the pattern.