One embodiment of the present invention is a thin film transistor having a gate electrode formed on an insulating substrate, a gate wire connected to the gate electrode, a capacitor electrode, a capacitor wire connected to the capacitor electrode, a gate insulator formed on the gate electrode, an oxide semiconductor pattern formed on the gate insulator, a sealing layer formed on the oxide semiconductor pattern, a drain electrode and a source electrode formed on the sealing layer, a drain wire connected to the drain electrode and a pixel electrode connected to the source electrode, the drain wire and the pixel electrode being in the same layer as the drain electrode and the source electrode. Wherein the gate wire, the capacitor electrode and the capacitor wire are in the same layer as the gate electrode, and wherein the sealing layer does not cover a connection part of the source electrode and a connection part of the drain electrode and wherein the drain electrode and the source electrode are connected to the oxide semiconductor pattern via the connection part of the drain electrode and the connection part of the source electrode.