A radiation-sensitive resin composition comprising (A) a resin comprising at least two recurring units of the formulas (1) (6) in the total amount of 5 70 mol %, but each in the amount of 1 49 mol %, the resin being insoluble or scarcely soluble in alkali, but becoming easily soluble in alkali by the action of an acid, and (B) a photoacid generator. ##STR00001## ##STR00002## wherein R.sup.1 is a hydrogen or methyl and R.sup.2 is a substituted or unsubstituted alkyl group having 1 4 carbon atoms. The resin composition is useful as a chemically amplified resist having high transmittance of radiation, sensitivity, resolution, dry etching resistance, and pattern profile.