The invention provides a high-precision display device having a reliable top- and single-gate TFT causing less current leakage. Part of a gate line 10 that crosses a semiconductor layer 103 acts as a gate electrode to form a TFT. The semiconductor layer 103 is connected to a data line 20 via a through-hole 140 on one side of the TFT and also connected to a contact electrode 107 via a through-hole 120 on the other side of the TFT. A floating electrode 30 is formed between the TFT and the through-hole 140 or between the TFT and the through-hole 120. The floating electrode 30 is formed on a layer above the semiconductor layer 103 with the use of the same material and at the same time as the gate electrode.