A positive resist composition including a resin component (A) having a structural unit (a0) represented by general formula (a0-1) (R represents a hydrogen atom, a C1-C5 alkyl group or a C1-C5 halogenated alkyl group; R1 represents a C3 or more branched alkyl group; and each of R2 and R3 independently represents an alkyl group, wherein R2 and R3 may be mutually bonded to form a polycyclic group) and/or general formula (a0-2) (R is the same as defined above; R8 represents a divalent linking group that contains no halogen atom; and R7 represents an acid dissociable, dissolution inhibiting group), and an acid generator (B1) consisting of a compound represented by general formula (b1) (Y1 represents a C1-C4 fluorinated alkylene group which may have a substituent; X represents a C3-C30 aliphatic cyclic group which may have a substituent; and A+ represents an organic cation).