A field-effect transistor including at least: a substrate; a source electrode; a drain electrode; a gate electrode; a semiconductor layer in contact with the source electrode and with the drain electrode; and a gate insulating layer insulating between the semiconductor layer and the gate electrode, wherein the semiconductor layer contains a carbon nanotube, and the gate insulating layer contains a polymer having inorganic particles bound thereto. Provided is a field-effect transistor and a method for producing the field-effect transistor, wherein the field-effect transistor causes decreased leak current and furthermore enables a semiconductor solution to be uniformly applied.