An individual identifier is easily provided in a semiconductor device capable of wireless communication. The semiconductor device includes a thin film transistor including a channel forming region, an island-like semiconductor film including a source region and a drain region, a gate insulating film, and a gate electrode; an interlayer insulating film; a plurality of contact holes formed in the interlayer insulating film which reach one of the source region and the drain region; and a single contact hole which reaches the other of the source region and the drain region, wherein a diameter of the single contact hole is larger than a diameter of each of the plurality of contact holes, and a sum of areas of bases of the plurality of contact holes is equal to an area of a base of the single contact hole.