A liquid crystal display device and a manufacturing method therefor are provided where the number of processes for manufacturing TFT substrates can be decreased and a high production yield can be attained. To attain these objects, an image signal bus-line includes at least a transparent conductive film and a semiconductor layer. A pattern of the transparent conductive film extends up to a thin film transistor to form its drain electrode, and a pattern of a semiconductor layer extends up to the transistor to form its source electrode. By virtue of these arrangements, the thin film transistor substrate can be manufactured using as little as three or four photolithography processes.