A thin-film transistor, a thin-film transistor sheet, an electric circuit, and a manufacturing method thereof are disclosed, the method comprising the steps of forming a semiconductor layer by providing a semiconductive material on a substrate, b) forming an isolating area, which is electrode material-repellent, by providing an electrode material-repellent material on the substrate, and c) forming a source electrode on one end of the insulating area and a drain electrode on the other end of the insulating area, by providing an electrode material.