A polymer which is obtained from a combination of (meth)acrylate having a bridged ring lactone group and (meth)acrylate having an acid leaving group with a hexafluoroalcohol group is used as a base resin to formulate a positive resist composition which when exposed to high-energy radiation and developed, exhibits a high sensitivity, a high resolution, and a minimal line edge roughness due to controlled swell during development. The composition also has excellent dry etching resistance.