A mercapto compound is represented by formula (1) (in formula (1), R1 and R2 each independently represent a hydrogen atom or an alkyl group; R3 and R4 each independently represent a hydrogen atom or a substituent; n represents 1 or 2; m represents an integer of 1 to 6; 1 represents an integer of 1 to 6; q represents 0 or 1; p represents 2 or 3; p+q represents 3; X represents a perfluoroalkyl group having 1 to 14 carbon atoms; when n is 2, structures of units represented by CR1R2 may be identical to or different from each other; and when m is 2 or more, structures of units represented by CR3R4 may be identical to or different from each other). The mercapto compound is novel and has excellent affinity for a fluorine-containing polymer and a fluorine-containing solvent.