A lithium anode of a thermal battery may include a metal alloy foam in which a plurality of pores is formed and including nickel (Ni), iron (Fe), chromium (Cr), and aluminum (Al) mixed in a predetermined composition ratio, and lithium impregnated into the metal alloy foam in a molten state and accommodated in the pores, wherein the chromium in the composition ratio may facilitate the impregnation of the lithium into the pores and reduce the reactivity of the metal alloy foam to the lithium at an operating temperature of the thermal battery, and the aluminum in the composition ratio may facilitate the impregnation of the lithium into the pores and prevent the lithium from penetrating into a surface of the metal alloy foam.