A positive resist composition including a base component (A) which exhibits changed solubility in an alkali developing solution under the action of acid and an acid-generator component (B) which generates acid upon exposure dissolved in an organic solvent (S), the base component (A) containing a polymeric compound (A1) including a structural unit (a0) derived from an acrylate ester having a cyclic group containing a sulfonyl group on the side chain thereof, a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group and a structural unit (a5) represented by general formula (a5-1) (Y1 represents an aliphatic hydrocarbon group; Z represents a monovalent organic group; a represents an integer of 1 to 3, and b represents an integer of 0 to 2, provided that a+b=1 to 3).