A salt represented by the formula (X): wherein Q1 and Q2 each independently represent a fluorine atom or a C1-C6 perfluoroalkyl group, L1 represents a C1-C17 divalent saturated hydrocarbon group in which one or more —CH2— can be replaced by —O— or —CO—, ring W1 represents a C4-C36 lactone ring, R3 is a C1-C6 alkyl group etc., t represents an integer of 0 to 2, Z+ represents an organic counter ion, and W10 represents a group represented by the formula (X-1): wherein L2 represents a single bond etc., ring W2 represents a C3-C36 saturated hydrocarbon ring in which one —CH2— is replaced by —CO— and in which one or more —CH2— can be replaced by —O— or —CO—, R1 represents a C1-C12 hydrocarbon group, R2 is a C1-C6 alkyl group etc., and s represents an integer of 0 to 2, or a group represented by the formula (X-2): wherein L3 represents a C1-C17 divalent saturated hydrocarbon group in which one or more —CH2— can be replaced by —O— or —CO—, ring W3 represents a C3-C36 saturated hydrocarbon ring, R4 is a hydroxyl group etc., R5 is a C1-C6 alkyl group etc., v represents an integer of 1 to 3, and w represents an integer of 0 to 2.