There is provided a negative electrode comprising an aluminum alloy, wherein the alloy has a magnesium content of 0.0001% by weight or higher and 8% by weight or lower, the alloy satisfies at least one condition selected from the group consisting of the following (A) and (B): (A) an iron content is 0.0001% by weight or higher and 0.03% by weight or lower, and (B) a silicon content is 0.0001% by weight or higher and 0.02% by weight or lower, and a content of each element other than aluminum, magnesium, silicon and iron in the alloy is 0.005% by weight or lower.