Provided is a display device that has a photodetection element within a pixel and can calibrate automatically a photo sensor signal during an operation of the display device. A sensor row driver (5) has a first operation mode for supplying a sensor drive signal of a first pattern to a photo sensor in a pixel region (1) and outputting a photo sensor signal corresponding to a quantity of receiving light to a signal processing circuit (8), a second operation mode for supplying a sensor drive signal of a second pattern and acquiring a first photo sensor signal level for calibration corresponding to the case where a black level is detected, and a third operation mode for supplying a sensor drive signal of a third pattern and acquiring a second photo sensor signal level for calibration corresponding to the case where a white level is detected. During the first operation mode, a third photo sensor signal level for calibration is acquired from a dummy pixel. The signal processing circuit (8) calibrates the photo sensor signal from an effective pixel during the first operation mode by using the first to third photo sensor signal levels.