A method for removing sulfur compounds including transferring the impurity gas to a concentration process in which the impurity gas is separated into a concentrated gas containing hydrogen sulfide and a residual gas containing carbon dioxide, mercaptans and aromatic hydrocarbons: transferring the concentrated gas to a Claus reaction process in which hydrogen sulfide is recovered as an elementary sulfur, and an off-gas discharged from the Claus reaction process is heated to a temperature between the discharge temperature and 700 C.; introducing the heated off-gas into a mixing unit provided downstream of the heating means to be mixed with the residual gas; transferring a resultant mixed gas to a hydrogenation reaction process in which sulfur compounds are converted into hydrogen sulfide under the presence of a reduction catalyst; and separating the converted hydrogen sulfide and returning the separated hydrogen sulfide to the Claus reaction process.