A method of producing a thin film transistor includes a gate electrode formation step that forms a gate electrode on a substrate, a gate insulating layer formation step that forms a gate insulating layer on the substrate in such a manner as to cover the gate electrode formed in the gate electrode formation step, a source/drain electrodes formation step that forms a source electrode and a drain electrode on the gate insulating layer, and a semiconductor layer formation step that applies an aqueous solution for semiconductor layer formation which is an aqueous solution comprising at least a single wall carbon nanotube and a surfactant between the source electrode and the drain electrode formed in the source/drain electrodes formation step by a coating process to form a semiconductor layer comprising the single wall carbon nanotube.