Abstract: An Mg—Li alloy contains more than 10.50% by mass and not more than 16.00% by mass of Li, not less than 2.00% by mass and not more than 15.00% by mass of Al, not less than 0.03% by mass and less than 1.10% by mass of Mn, impurities, and the balance of Mg. The impurities contain Fe at a concentration of 15 ppm or less. The alloy may optionally contain M, which is at least one element selected from the group consisting Ca, Zn, Si, Y, and rare earth metal elements with atomic numbers of 57 to 71.