A touch panel whose power consumption can be reduced is provided, and an increase in the manufacturing cost of the touch panel is prevented. A photosensor which includes a light-receiving element including a non-single-crystal semiconductor layer between a pair of electrodes and a transistor including an oxide semiconductor layer in a channel formation region is provided. A touch panel which includes a plurality of pixels and the photosensor adjacent to at least one of the plurality of pixels is provided. Each of the plurality of pixels includes a pair of terminals. One of the pair of terminals is a reflective conductive film. Alternatively, each of the pair of terminals is a light-transmitting conductive film.