A thin film transistor is provided as follows. A first gate electrode and a second gate electrode are stacked on each other. A semiconductor layer is interposed between the first and second gate electrodes. A source electrode and a drain electrode are interposed between the semiconductor layer and the second gate electrode. A connection electrode connects electrically the first gate electrode and the second gate electrode. A first insulating film is interposed between the first gate electrode and the semiconductor layer. A second insulating film includes a first part interposed between the semiconductor layer and the second gate electrode and a second part interposed between the second gate electrode and the drain electrode. A third insulating film includes a first part interposed between the connection electrode and the second gate electrode.