A field-effect type transistor has: a source electrode; a drain electrode being a metal electrode; a semiconductor layer provided to be in contact with both of the source electrode and the drain electrode; and a gate electrode provided to face at least a part of the semiconductor layer. The gate electrode has: a first gate electrode; and a second gate electrode provided closer to the drain electrode than the first gate electrode is. The second gate electrode is so connected as to have a same potential as the drain electrode and is electrically isolated from the first gate electrode. Consequently, in a display device, the off-leakage current is suppressed, and reduction in a pixel area and a bus interconnection width is suppressed.