1. A radiation-sensitive resin composition comprising: (A) a resin insoluble or scarcely soluble in alkali, but becomes alkali soluble by the action of an acid and (B) a photoacid generator. The resin comprises (a) at least one recurring unit of the following formula (1-1) or (1-2), ##STR00001## and (b) at least one recurring unit for the following formula (2-1), (2-2), or (2-3). ##STR00002##