PURPOSE: To safely produce anhydrous sodium polysulfide at a low cost by dissolving anhydrous sodium sulfide in a mixed solvent composed of a solvent having no or little dissolving power to sodium sulfide and a solvent capable of dissolving sodium sulfide and having a boiling point lower than that of the former solvent, adding sulfur to the solution and distilling out the dissolving solvent after reaction.

CONSTITUTION: Anhydrous sodium sulfide is dissolved in a mixed solvent composed of the 1st solvent having no or little dissolving power to sodium sulfide and the 2nd solvent capable of dissolving sodium sulfide and having higher boiling point than the 1st solvent. Sulfur is dissolved in the obtained solution and the 2nd solvent is distilled off. The 1st solvent is preferably one or more solvents selected from halogenated hydrocarbons, ethers and ketones and the 2nd solvent is preferably one or more solvents selected from lower alcohols.