A battery with a high capacity and superior cycle characteristics, and an anode active material used for it are provided. An anode active material contains tin as a first element, a second element, and a third element. The second element is at least one from the group consisting of boron, carbon, aluminum, and phosphorus, and the third element is at least one from the group consisting of silicon, magnesium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, zirconium, niobium, molybdenum, silver, indium, cerium, hafnium, tantalum, tungsten, and bismuth. The content of the second element in the anode active material is from 9.8 wt % to 49 wt %.