An anodized aluminum alloy sheet exhibits excellent surface quality without showing a band-like streak pattern and is formed from a 5000 series aluminum alloy sheet that includes 1.0 to 6.0 mass % of Mg, wherein the concentration of Mg in a solid-solution state that is present in an outermost surface area of the aluminum alloy sheet varies in the widthwise direction of the aluminum alloy sheet in the form of a band having a width of 0.05 mm or more, and the difference in the concentration of Mg between adjacent bands is 0.20 mass % or less.