To fabricate a high mobility organic thin film transistor in which positional precision of a semiconductor layer is enhanced by preventing impairment of the semiconductor layer caused by the process in a bottom contact type organic thin filter transistor element.

In the fabrication process of an organic thin filter transistor, a water repellent pattern is formed on a source electrode and a drain electrode, organic semiconductor solution is introduced between the source electrode and the drain electrode and then the solvent is removed thus forming an organic semiconductor layer.