To provide a method for producing 4,4'-BPS, comprising reacting phenol with sulfuric acid in an aliphatic saturated hydrocarbon solvent under refluxing, which enables the efficient removal of the by-produced water and the improvement in the yield of the 4,4'-BPS by using such proper mixed solvents as enhancing the yield of the 4,4'-BPS in the reaction process and the subsequent process.

This method for producing 4,4'-bisphenolsulfone, comprising reacting phenol with sulfuric acid in mixed solvents comprising an aliphatic saturated hydrocarbon having a boiling point of ≥175°C and a solvent capable of dissolving the phenol and having a boiling point of ≤170°C under refluxing, while removing the by-produced water, and distilling off the solvent capable of dissolving the phenol and having a boiling point of ≤170°C from the reaction system. It is preferable that the solvent capable of dissolving the phenol and having a boiling point of ≤170°C is distilled off from the reaction system after the reaction is finished. Isoper H [trade mark of Exon Chem. (KK)] is preferable as the aliphatic saturated hydrocarbon.