To make it possible to form a metal electrode of low electrical contact resistance on a conductive indium-containing oxide semiconductor layer constituting a device active layer of a thin-film transistor or the like. Between an indium-containing oxide semiconductor layer and a metal electrode layer provided above this layer for passing device operating current, which can reduce indium oxide or the like of the oxide semiconductor layer. A metallic oxide layer and a metal layer are formed using as material a metal film including an easily oxidable metal, and further an indium-rich layer in which reduced indium is accumulated is formed at a boundary between the metallic oxide layer and the metal layer.