Abstract: A thin-film transistor panel is constituted by forming, on an insulating substrate, a plurality of thin-film transistors, a plurality of gate lines for each connecting gate electrodes of the thin-film transistors, and a plurality of pixel electrodes formed of a transparent conductive film connected to the thin-film transistors, then forming a low-resistance metal film of an Al or Al alloy for a data line and a surface metal film of Cr with a high density, forming a photoresist film of a predetermined pattern on the surface metal film, and etching the data line metal film and surface metal film. Then, the surface metal film remaining on the data line metal film is eliminated.