The present invention provides a thin film transistor, wherein the semiconductor channel region is patterned. Gate electrodes 102, gate insulating film 103, source electrodes 104, and drain electrodes 105 are formed on a glass substrate 101. A patterned insulating film is formed thereon, and a part of the film in the region 110 on the gate electrode is removed. An organic semiconductor film is formed thereon by vapor deposition. The organic semiconductor film 107 in the region 110, where the patterned insulating film is removed, becomes a channel region, and is separated from the organic semiconductor film 108 on the patterned insulating film 106. Therefore, the organic semiconductor channel region is patterned to have the same size as the gate electrode. In accordance with the present invention, a thin film transistor, wherein the semiconductor region is patterned precisely, becomes available.