A metal foil including: a steel layer whose thickness is 10 to 200 μm; an alloy layer which contains Fe and Al and which is formed on the steel layer; and an Al-containing metal layer arranged on the alloy layer, wherein, when a cutting-plane line of a surface of the Al-containing metal layer is defined as a contour curve and an approximation straight line of the contour curve is defined as a contour average straight line, a maximum point, whose distance from the contour average straight line is more than 10 μm, is absent on the contour curve, and a thickness of the alloy layer is 0.1 to 8 μm and the alloy layer contains an Al7Cu2Fe intermetallic compound or FeAl3 based intermetallic compounds.