A positive resist composition including a base component (A) which exhibits increased solubility in an alkali developing solution under action of acid and an acid-generator component (B) which generates acid upon exposure, the component (A) including a polymeric compound (A1) having an acid dissociable, dissolution inhibiting group in the structure thereof and including a structural unit (a0) having an —SO2— containing cyclic group on the terminal of the side chain, and the component (B) including an acid generator (B1) containing a compound represented by general formula (b1-1) (R0 represents a hydrocarbon group of 1 to 12 carbon atoms which may have a substituent, provided that the carbon atom adjacent to the sulfur atom within the —SO3− group has no fluorine atom bonded thereto, and Z+ represents an organic cation). R0—SO3−Z+  (b1-1)