Provided is a display device that has excellent accuracy in image capturing by improving linearity of sensitivity characteristics of a photodiode. An optical sensor provided on an active matrix substrate of the display device includes; a photodiode (D1a) for receiving incident light; a reset signal line (RSTa) for supplying a reset signal RST to the optical sensor; a readout signal line (RWSa) for supplying a readout signal RWS to the optical sensor; and a sensor switching element (M1a) for reading out a photoelectric current output from the photodiode (D1a), according to the readout signal, during a period from the supply of the reset signal to the supply of the readout signal. A potential VLS of a light shielding film (LS) provided on a back side of the photodiode (D1a) is caused to be a high level potential during a period that at least partially overlaps a period while the reset signal is supplied.