To provide a positive resist composition having high sensitivity and capable of satisfying no pattern collapse and good exposure latitude, and a pattern forming method using the positive resist composition.

The positive resist composition comprises (A) a resin (A1) having a repeating unit (a1) of a structure selected from general formulae (pI)-(pV) and a resin (A2) having a repeating unit (a2) different from the repeating unit (a1) as resins of which the solubility in an alkali developer increases under the action of an acid, (B) a compound capable of generating an acid upon irradiation with actinic rays or radiation, and (C) a solvent. The pattern forming method using the positive resist composition is also provided.