To achieve, in an oxide semiconductor thin layer transistor, both the stability of threshold voltage against electric stress and suppression of variation in the threshold voltage in a transfer characteristic. A thin film transistor includes an oxide semiconductor layer and a gate insulating layer disposed so as to be in contact with the oxide semiconductor layer, wherein the oxide semiconductor layer contains hydrogen atoms and includes at least two regions that function as active layers of the oxide semiconductor and have different average hydrogen concentrations in the layer thickness direction; and when the regions functioning as the active layers of the oxide semiconductor are sequentially defined as, from the side of the gate insulating layer, a first region and a second region, the average hydrogen concentration of the first region is lower than the average hydrogen concentration of the second region.