Dynamic range is widened in a display device with a photosensor that can read an image due to having a photodetection element inside a pixel thereof. A sensor driving circuit switches ON a reset signal (RST) that is supplied via reset signal bus line, and after a predetermined time has elapsed, switches ON a readout signal (RWS) that is supplied via readout signal bus line. Thus, in the photosensor, from which a photosensor signal is output in accordance with an amount of light received by the photosensor in the predetermined time, the capacitance of a capacitor provided in the photosensor is made variable from when the reset signal (RST) is supplied to the photosensor until when the predetermined time has elapsed.