An organic FET 1 comprises a substrate 2 on which a gate insulation film 41 and a reformed layer 43 are formed in this order, and a source electrode 6 and a drain electrode 8 are further arranged thereon at a predetermined distance from each other, and furthermore, an organic semiconductor layer 10 is formed on and between the electrodes 6 and 8. The reformed layer 43 fixed on the gate insulation film 41 and attached to the organic semiconductor layer 10 contains a specific compound containing the CN group or is composed of only a specific compound containing the CN group.