Disclosed is a method for manufacturing a thin film transistor having high resolution and high pattern accuracy with high production efficiency. Particularly disclosed is a method for manufacturing a thin film transistor wherein there is prevented deterioration of semiconductor properties in a plating step for electrode formation. This method is characterized in that a source electrode or a drain electrode is formed by such a process wherein a protective film is formed on an organic semiconductor layer, then a plating catalyst pattern is formed thereon by supplying a liquid containing a plating catalyst, and then a plating agent is brought into contact with the pattern.