A display device of the invention includes a display panel 10 and a touch panel 22. A detector circuit 50 has switches 411 and 412. Switches 411 and 412 are alternately turned on and off repeatedly in the setting period. Touch detection is performed during a counting period that follows the setting period on the basis of required time until a voltage at the node reaches a reference voltage while the switch 411 is turned off and switch 412 is turned on. Common voltage changes in the setting period while switch 411 is turned off and switch 412 is turned on.