To achieve an input device with a simpler configuration.

In the display part 13 of a display device, a plurality of switching circuits 61 are arranged in the shape of a matrix correspondingly to an input area, and turned on or off in accordance with received light quantity. Voltage detecting parts 51x and 51y detect voltage that is changed when a predetermined switching circuit 61 among the plurality of switching circuits 61 arranged in the shape of a matrix is turned on or off in each x direction and y direction. A position detecting part detects a position in an input area input by a user from detection results of the voltage detecting parts 51x and 51y. The invention is applicable, for example, to a display device which displays video and to which input is made.