The present invention provides a field effect transistor that includes a semiconductor layer (15) containing an organic substance, and a first electrode (16), a second electrode (12), and a third electrode (14) that are not in contact with each other at least electrically. The first electrode (16) is arranged above the semiconductor layer (15), the second electrode (12) is arranged below the semiconductor layer (15), and the third electrode (14) is arranged beside the semiconductor layer (15). The semiconductor layer (15) is connected electrically to two electrodes selected from the first electrode (16), the second electrode (12), and the third electrode (14), and the electrically insulating layers (13,17) are interposed between the electrodes (12, 14, 16). The first electrode (16) lies over the semiconductor layer (15) so as to extend beyond the periphery of the semiconductor layer (15). With this configuration, it becomes possible to provide a field effect transistor that is highly resistant to air and water and thus has a long lifetime even though an organic semiconductor is used therein, and a display device using such a field effect transistor.