A positive resist composition, includes: (A) a compound capable of generating an acid upon irradiation with actinic rays or radiation; (B) a resin of which solubility in an alkali developer increases under an action of an acid, the resin containing 80 mol % or more of an aromatic group-free copolymerization component; and (C) a compound capable of decomposing under an action of an acid to generate an acid, wherein an absolute value of difference in pKa between the acid generated from the component (A) and the acid generated from the component (C) is 2 or less, and an absolute value of difference in molecular weight between the acid generated from the component (A) and the acid generated from the component (C) is 50 or less.