Provided is an active matrix substrate that includes a substrate, a thin film transistor, an electrode layer, and a second insulating film. The thin film transistor is provided on the substrate and includes an oxide semiconductor layer, a gate electrode, and source and drain electrodes. The oxide semiconductor layer includes a first region as a channel region. The electrode layer is level with the gate electrode, is provided in a different region from the thin film transistor, and includes a first end. The second insulating film is provided between the substrate and the electrode layer and includes a second end at a more retreated position than the first end of the electrode layer. The oxide semiconductor layer further includes a second region having lower resistance than the first region. The electrode layer is electrically coupled, at the first end, to the second region of the oxide semiconductor layer.