A TFT array substrate used for a display device and a method of making the same are disclosed. A optically transparent thick resin insulation film 5 is formed on a base substrate and an upper contact hole 51 is perforated through the optically transparent thick resin insulation film 5. A lower contact hole 41 perforated through a gate insulation film 15 and patterning of an ITO film to make a transparent pixel electrode are then collectively carried out under a photoresist pattern 8. Where the photoresist pattern 8 is provided after making the ITO film, an aperture 81 is perforated closer to the center of the upper contact hole 51 at an end portion of a connecting line 14a for a pad and is smaller in diameter by a side etching size plus a margin than the upper contact hole. Subsequently, following three-etching steps are carried out: (1) patterning of the ITO film along the photoresist pattern 8, (2) the lower contact hole 41 is made by using buffered hydrofluoric acid solution, and (3) an "eaves" portion 6a of the ITO films is removed.