Provided is an oxide-semiconductor-based thin film transistor having satisfactory switching characteristics and stress resistance. Change in threshold voltage through stress application is suppressed in the thin film transistor. The thin film transistor of excellent stability comprises a substrate and, formed thereon, at least a gate electrode, a gate insulating film, oxide semiconductor layers, a source-drain electrode, and a passivation film for protecting the gate insulating film, and oxide semiconductor layers, wherein the oxide semiconductor layers are laminated layers comprising a second oxide semiconductor layer consisting of In, Zn, Sn, and O and a first oxide semiconductor layer consisting of In, Ga, Zn, and O. The second oxide semiconductor layer is formed on the gate insulating film. The first oxide semiconductor layer is interposed between the second oxide semiconductor layer and the passivation film.