A touch panel including an oxide semiconductor film having conductivity is provided. The touch panel includes a transistor, a second insulating film, and a touch sensor. The transistor includes a gate electrode; a gate insulating film; a first oxide semiconductor film; a source electrode and a drain electrode; a first insulating film; and a second oxide semiconductor film. The second insulating film is over the second oxide semiconductor film so that the second oxide semiconductor film is positioned between the first insulating film and the second insulating film. The touch sensor includes a first electrode and a second electrode. One of the first and second electrodes includes the second oxide semiconductor film.