PURPOSE: To manufacture economically metallic lithium of high quality by feeding lithium carbonate combined with a reducing agent to the surface of an electrolytic bath in the anode chamber of an electrolytic cell in which gaseous chlorine is generated.

CONSTITUTION: A mixed molten salt contg. lithium chloride and potassium chloride is electrolyzed in the anode chamber of an electrolytic cell to manufacture metallic lithium and gaseous chloride. At this time, lithium carbonate combined with a reducing agent is fed to the surface of the molten salt bath in the anode chamber in place of lithium chloride as a starting material. The lithium carbonate is converted into lithium chloride by chlorination with gaseous chlorine generated by electrolysis to replenish lithium chloride consumed by electrolysis. The manufacturing cost of metallic lithium is reduced by using inexpensive lithium carbonate with low hygroscopicity in place in lithium chloride.