An object of the invention is to provide a method for manufacturing a thin film transistor in a self-aligning manner by using the droplet discharging method regardless of the accuracy of a discharge position for a droplet discharging device. In view of the object, an organic resin film or the like is applied and processed into a predetermined shape by etch-back, exposure, development and the like. By utilizing the organic resin film with the predetermined shape as a mask, a semiconductor layer containing an impurity of one conductivity type is etched. By utilizing the organic resin film with the predetermined shape, regions with different wettabilities are formed.