A positive resist composition comprising: a resin which increases solubility in an alkali developing solution by an action of an acid and comprises a repeating unit containing a lactone structure and a cyano group, a repeating unit containing a first group selected from groups represented by the formulae (pI) to (pV) as defined herein and a repeating unit containing a second group selected from groups represented by the formulae (pI) to (pV) as defined herein which is different from the first group; a compound which generates an acid upon irradiation of an actinic ray or a radiation; and a solvent.