The present invention relates to a chemically amplified polymer having a pendent group with dicyclohexyl bonded thereto, a process for the preparation thereof, and a resist composition comprising it, and more particularly, to a novel (meth)acrylic or norbornene carboxylate compound with dicyclohexyl bonded thereto, a process for the preparation thereof, a chemically amplified polymer synthesized therewith, and a positive photoresist composition for ArF comprising said polymer, with high resolution and excellent etching resistance.