A semiconductor device comprising: a conductive film functioning as an antenna; a power source generating circuit electrically connected to the conductive film functioning as an antenna; an integrated circuit and a display element electrically connected to the power source generating circuit; a constant voltage circuit for supplying a first voltage to the integrated circuit; a displaying power source circuit for supplying a second voltage to the display element; a first thin film transistor provided in the power source generating circuit; a second thin film transistor provided in the integrated circuit; a third thin film transistor provided in the display element; an insulating film provided to cover the first thin film transistor, the second thin film transistor, and the third thin film transistor; a source electrode and a drain electrode of the first thin film transistor, a source electrode and a drain electrode of the second thin film transistor, and a source electrode and a drain electrode of the third thin film transistor which are formed over the insulating film; and a pixel electrode electrically connected to the source electrode or the drain electrode of the third thin film transistor, wherein the source electrode or the drain electrode of the first thin film transistor is electrically connected to the conductive film functioning as an antenna, wherein the first thin film transistor includes a first semiconductor film, a first gate insulating film provided over the first semiconductor film, and a first gate electrode provided over the first gate insulating film, wherein the second thin film transistor includes a second semiconductor film, a second gate insulating film provided over the second semiconductor film, and a second gate electrode provided over the second gate insulating film, wherein the third thin film transistor includes a third semiconductor film, a third gate insulating film provided over the third semiconductor film, and a third gate electrode provided over the third gate insulating film, the semiconductor device characterized in that the third gate insulating film is different in thickness from the first gate insulating film and the second gate insulating film. a conductive film functioning as an antenna; a power source generating circuit electrically connected to the conductive film functioning as an antenna; an integrated circuit and a display element electrically connected to the power source generating circuit; a constant voltage circuit for supplying a first voltage to the integrated circuit; a displaying power source circuit for supplying a second voltage to the display element; a first thin film transistor provided in the power source generating circuit; a second thin film transistor provided in the integrated circuit; a third thin film transistor provided in the display element; an insulating film provided to cover the first thin film transistor, the second thin film transistor, and the third thin film transistor; a source electrode and a drain electrode of the first thin film transistor, a source electrode and a drain electrode of the second thin film transistor, and a source electrode and a drain electrode of the third thin film transistor which are formed over the insulating film; and a pixel electrode electrically connected to the source electrode or the drain electrode of the third thin film transistor, wherein the source electrode or the drain electrode of the first thin film transistor is electrically connected to the conductive film functioning as an antenna, wherein the first thin film transistor includes a first semiconductor film, a first gate insulating film provided over the first semiconductor film, and a first gate electrode provided over the first gate insulating film, wherein the second thin film transistor includes a second semiconductor film, a second gate insulating film provided over the second semiconductor film, and a second gate electrode provided over the second gate insulating film, wherein the third thin film transistor includes a third semiconductor film, a third gate insulating film provided over the third semiconductor film, and a third gate electrode provided over the third gate insulating film, the semiconductor device characterized in that the third gate insulating film is different in thickness from the first gate insulating film and the second gate insulating film.