A resist composition which is stable relative to solvents used in
immersion lithography processes and displays excellent sensitivity and
resist pattern profile, and a method of forming a resist pattern that
uses such a resist composition are provided. The resist composition is in
accordance with predetermined parameters, or is a positive resist
composition comprising a resin component (A) which contains an acid
dissociable, dissolution inhibiting group and displays increased alkali
solubility under the action of acid, an acid generator component (B), and
an organic solvent (C), wherein the component (A) contains a structural
unit (a1) derived from a (meth)acrylate ester containing an acid
dissociable, dissolution inhibiting group, but contains no structural
units (a0), including structural units (a0-1) containing an anhydride of
a dicarboxylic acid and structural units (a0-2) containing a phenolic
hydroxyl group.