An organic thin-film transistor manufacturing method and an organic thin-film transistor manufactured by the method are disclosed, the method comprising the steps of a) forming a gate electrode on a substrate, b) forming a gate insulating layer on the substrate, c) forming an organic semiconductor layer on the substrate, d) forming an organic semiconductor layer protective layer on the organic semiconductor layer, e) removing a part of the organic semiconductor layer protective layer, and f) forming a source electrode and a drain electrode at portions where the organic semiconductor layer protective layer has been removed, so that the source electrode and drain electrode contacts the organic semiconductor layer.