A thin film transistor of the present invention is a thin film transistor (100) having a semiconductor layer (14), a source region (15) and a drain region (16) provided to be isolated from each other so as to mutually oppose the semiconductor layer. The semiconductor layer has .pi.-conjugated organic semiconductor molecules as its main component. The .pi.-conjugated organic semiconductor molecules are oriented so that .pi. orbitals substantially oppose each other and that the molecular axis of the main chains is oriented to be inclined with respect to a direction of electric field in a channel formed in the semiconductor layer.