A thin-film transistor array substrate according to one embodiment of the present invention comprises: an active layer; a middle layer; a gate insulation film; a gate electrode; an interlayer insulation film; a source electrode; and a drain electrode. The active layer is positioned on the substrate and the gate insulation film is positioned on the active layer. The gate electrode is positioned on the gate insulation film and the interlayer insulation film is positioned on the gate electrode. The source electrode and drain electrode are positioned on the interlayer insulation film and are connected to the active layer. The middle layer is positioned between the active layer and gate insulation film and is made of oxide semiconductor comprising Group IV elements.
