Provided are an organic thin film transistor that has high bendability and can suppress a decrease in carrier mobility caused by a pinhole of an insulating film or leveling properties and a method of manufacturing the organic thin film transistor. The organic thin film transistor includes: a gate electrode; an insulating film that is formed to cover the gate electrode; an organic semiconductor layer that is formed on the insulating film, and a source electrode and a drain electrode that are formed on the organic semiconductor layer, in which the insulating film includes an inorganic film consisting of SiNH.