Resist composition and method for forming resist pattern

A resist composition comprising a resin component (A) that undergoes a change in alkali solubility in the presence of acid, and an acid generator component (B) that generates acid on exposure, wherein:

• said resin component (A) has a weight average molecular weight of no more than 7,500 and comprises structural units (a) derived from a (meth)acrylate ester,
• wherein said structural units (a) comprise a structural unit (a1) derived from a (meth)acrylate ester containing an acid dissociable, dissolution inhibiting group which is represented by the following general formula (I),
• wherein, R represents a hydrogen atom or a methyl group, and R1 represents a lower alkyl group of 2 to 5 carbon atoms,
• a structural unit (a2) derived from a (meth)acrylate ester comprising a lactone-containing polycyclic group, and
• a structural unit (a3) derived from a (meth)acrylate ester comprising a hydroxyl group-containing aliphatic hydrocarbon group;
• and wherein
• said component (B) comprises a sulfonium compound represented by a general formula (b-1) shown below:
• wherein, X represents a perfluoroalkylene group of 3 carbon atoms;
• R1 to R3 each represents, independently, an aryl group or an alkyl group, and at least one of R1 to R3 represents an aryl group.