By using one photo mask in the manufacturing steps of a liquid crystal display device, steps such as resist coating, prebaking, exposure, development, and postbaking, as well as the formation of a covering film, etching, resist peeling, rinsing, drying and the like before and after the aforementioned steps are required, which make the process complicated. To solve the problem, a channel-etch type bottom gate TFT (inverted staggered TFT) is employed to pattern source and drain regions and a pixel electrode with the same mask. Moreover, according to the invention, among the patterns required to form a liquid crystal display device such as a conductive layer for a wiring layer or an electrode, a mask for forming a predetermined pattern and the like, at least one or more of them is formed by a method by which a pattern can selectively be formed, thereby manufacturing a liquid crystal display device.