To provide a radial ray-sensitive resist composition that has a high resolution and a high sensitivity and gives resist patterns having excellent pattern shapes and high etching resistance and a polymer to be used therefor.

The objective resist composition comprises (A) a polymer that has a structural unit including a group represented by general formula [1] (wherein individual symbols are defined in the patent specification) and (B) an acid-generating agent and the vinylic polymer to be used in the resist composition has a structural unit represented by general formula [2] (individual symbols are defined in the patent specification).