To provide flux for treating aluminum molten metal with which the generation of harmful gaseous chlorine or the like in aluminum molten metal can be reduced while hydrogen and nonmetallic inclusions therein are removed so as to perform purifying, and to provide a treatment method for aluminum molten metal using the same.

The flux for treating aluminum molten metal consists of, by weight, 3 to 10% NaF (fluoride), and chlorides of 40 to 60% KCl and 40 to 60% NaCl. The interfacial tension (σM) between aluminum molten metal and the flux is ≤550 mN/m.