Active matrix substrate and X-ray imaging panel including same

An active matrix substrate 1 includes photoelectric conversion elements that are respectively provided with respect to a plurality of pixels defined by gate lines and data lines 10, and a bias line 13 supplying a bias voltage to each photoelectric conversion element. Further, the active matrix substrate 1 further includes a plurality of data protection circuit units 16a that are connected with the data lines 10, respectively, and a first common line 17a that is connected with the data protection circuits 16a and has a potential equal to or lower than those of the data lines 10, outside the image pickup area composed of a plurality of pixels. The data protection circuit unit 16a includes a first data non-linear element 161a, and the first data non-linear element 161a is connected in a reverse bias state between the first common line 17a and the data lines 10.