The present invention relates to a resist resin having an acid-decomposable group, which gives rise to decomposition of the acid-decomposable group to show an increased solubility to an aqueous alkali solution by the action of an acid, wherein the resist resin has, in the main chain, an alicyclic lactone structure represented by the following general formula (1). According to the present invention, a positive-type chemically amplified resist can be obtained which has high transparency to a far-ultraviolet light having a wavelength of about 220 nm or less, excellent etching resistance, and excellent adhesion to substrate; and a fine pattern required in production of semiconductor device can be formed. ##STR1##

(wherein Z is an alicyclic hydrocarbon group having a lactone structure).