The present invention provides a salt of the formula (I): ##STR00001## wherein X represents alkylene group or substituted alkylene group; Q.sup.1 and Q.sup.2 each independently represent fluorine atom or perfluoroalkyl group having 1 to 6 carbon atoms; A.sup.+ represents organic counter ion; and n shows 0 or 1.The present invention also provides a chemically amplified resist composition comprising the salt of the formula (I), and a resin which contains a structural unit having an acid-labile group and which itself is insoluble or poorly soluble in an alkali aqueous solution but becomes soluble in an alkali aqueous solution by the action of an acid.