Abstract: A structure which prevents the distortion of the TFT characteristics caused by an electric charge formed on the surface of a protecting layer which exists on the TFT and a method for manufacturing the TFT. A switching device of an X-ray sensor comprises a TFT provided on a transparent substrate, a first protecting insulation layer which covers the TFT, storage capacity electrodes connected to a ground wire on the first protecting insulation layer, a second protecting insulation layer which covers the storage capacity electrode formed on the first protecting insulation layer, and a pixel electrode connected to one terminal of the TFT on the second protecting insulation layer, at least one portion of the storage capacity electrodes shielding the TFT region.