Provided is a method that is for producing hexafluoro-1,3-butadiene, discharges small amounts of industrial wastes, and is industrially applicable. The method for producing hexafluoro-1,3-butadiene includes a reaction step of reacting a halogenated butane represented by chemical formula, CF2X1-CFX2-CFX3-CF2X4 (X1, X2, X3, and X4 are each independently a halogen atom other than a fluorine atom) in an organic solvent in the presence of zinc to eliminate the halogen atoms, X1, X2, X3, and X4, other than the fluorine atoms to generate hexafluoro-1,3-butadiene, giving a reaction product containing the hexafluoro-1,3-butadiene, and an aftertreatment step of separating the hexafluoro-1,3-butadiene from the reaction product produced in the reaction step, then adding water to a reaction product residue after the separating, and removing the organic solvent, giving an aqueous solution of zinc halide.