An organic FET 1 comprises a substrate 2 on which a gate insulation film 41 and a functional 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 functional layer 43 provided so as to come into contact with the organic semiconductor layer 10 is composed of matrix polymers such as PMMA in which electron acceptors such as p-bromanil are contained.