The present invention relates to an organic thin film transistor which includes an organic layer comprising an organic compound facilitating the ohmic contact between a semi-conducting layer and electrodes and serving as the semi-conducting layer.The organic thin film transistor according to the present invention has excellent electric contact between the semiconductor layer and the source electrode/drain electrode, and thus can be widely used as components for electric/electronic devices. As a result, as the materials for the source electrode or the drain electrode in the organic thin film transistor, materials which are less expensive and excellent in processibility though they have a low work function as the materials can be used.