A display device includes a metal conductive layer formed on a substrate, a transparent electrode film formed on the substrate and joined to the metal conductive layer and an interlayer insulating film isolating the metal conductive layer and the transparent conductive film. The metal conductive layer has a lower aluminum layer made of aluminum or aluminum alloy, an intermediate impurity containing layer made of aluminum or aluminum alloy containing impurities and formed on a substantially entire upper surface of the lower aluminum layer and an upper aluminum layer made of aluminum or aluminum alloy and formed on the intermediate impurity containing layer. In the interlayer insulating film and the upper aluminum layer, a contact hole penetrates therethrough and locally exposes the intermediate impurity containing layer, and the transparent electrode film is joined to the metal conductive layer in the intermediate impurity containing layer exposed from the contact hole.