A method of manufacturing a transistor includes disposing a droplet containing a bank material as a solute or a dispersoid on a substrate, drying the droplet to form a bank, ejecting a conductive material on a part of the bank to form a first conductive region and a second conductive region with the part of the bank interposed therebetween, removing the bank to form a groove between the first and second conductive regions, supplying a semiconductor material into the groove to form a semiconductor film, forming a gate insulating film on the semiconductor film, and forming a gate electrode at a position on the gate insulating film facing the semiconductor film.