To provide an acid generator and a
resist composition capable of producing a
resist pattern having good
line edge roughness.SOLUTION: The acid generator contains a salt represented by formula (I). [wherein, m10 is an integer of 1 to 3, and m11 is an integer of 0 to 2; A1 / A2 is a bond or a hydrocarbyl group; Ar1 / Ar2 is an aromatic hydrocarbyl group or the like; R1 / R4 is a
hydroxy group, - X1 - or the like, is - CO-O -, - O-CO - or the like, and is a substituted / unsubstituted hydrocarbyl group; is an acid-labile group; and and are each a
halogen atom, a hydrocarbyl group, or a group formed by mutually bonding and and containing X +; R3 R10 R2 R2 X1 R3 R10 L11, -CH2 - in the ring may be replaced by -O -, - S -, - SO2 -, - SO -, - CO - or the like; m1 is an integer of 1 to 5, mm1 is an integer of 2 to 5, m2 is an integer of 0 to 4, m3 and m4 are integers of 0 to 5, and mm4 is an integer of 0 or 1; and the AI - represents an organic cation. ] SELECTED DRAWING: None