A plurality of wires and electrodes are formed by forming a first conductive film, selectively forming a resist over the first conductive film, forming a second conductive film over the first conductive film and the resist, removing the second conductive film formed over the resist by removing the resist, forming a third conductive film so as to cover the second conductive film formed over the first conductive film, and selectively etching the first conductive film and the third conductive film. Thus, wires using a low resistance material can be formed in a large-sized panel, and thus, a problem of signal delay can be solved.