Positive resist composition

A positive resist composition comprising (A) a resin, which increases a solubility rate in an alkali developing solution by the action of an acid, containing a repeating unit represented by formula (I) shown below, a repeating unit represented by formula (II) shown below and a repeating unit represented by formula (III) shown below, and (B) a compound that generates an acid upon irradiation of an actinic ray or radiation

• wherein, R represents a hydrogen atom or a methyl group;
• A represents a single bond or a connecting group;
• and ALG represents any one of the groups represented by the following formulae (pI) to (pV):
• wherein, R11 represents a methyl group, an ethyl group, an n-propyl group, an isobutyl group or a sec-butyl group;
• Z represents an atomic group necessary for forming an alicyclic hydrocarbon group together with the carbon atom;
• R12 to R16 each independently represent a straight chain or branched alkyl group having from 1 to 4 carbon atoms or an alicyclic hydrocarbon group, provided that at least one of R12 to R14, and either R15 or R16 represents an alicyclic hydrocarbon group;
• R17 to R21 each independently represent a hydrogen atom, a straight chain or branched alkyl group having from 1 to 4 carbon atoms or an alicyclic hydrocarbon group, provided that at least one of R17 to R21 represents an alicyclic hydrocarbon group, and either R19 or R21 represents a straight chain or branched alkyl group having from 1 to 4 carbon atoms or an alicyclic hydrocarbon group;
• and R22 to R25 each independently represent a straight chain or branched alkyl group having from 1 to 4 carbon atoms or an alicyclic hydrocarbon group, provided that at least one of R22 to R25 represents an alicyclic hydrocarbon group, or R23 and R24 may be combined with each other to form a ring;
• wherein, R represents a hydrogen atom or a methyl group;
• A represents a single bond or a connecting group;
• and BLG represents a chain tertiary alkyl group;
• wherein, R30 represent a hydrogen atom or a methyl group;
• R31 to R33 each independently represent a hydrogen atom, a hydroxy group or an alkyl group, provided that at least one of R31 to R33 represents a hydroxy group.