A salt represented by the formula (a): wherein Q1 and Q2 each independently represent a fluorine atom etc., X1 represents a single bond etc., X2 represents a single bond etc., Y1 represents a C3-C6 alicyclic hydrocarbon group etc., with the proviso that —X2—Y1 group has one or more fluorine atoms, and Z+ represents an organic counter cation, and a photoresist composition comprising the salt represented by the formula (a) and a resin comprising a structural unit having an acid-labile group and being insoluble or poorly soluble in an aqueous alkali solution but becoming soluble in an aqueous alkali solution by the action of an acid.