An organic semiconductor device Including an organic semiconductor layer in a crystallized crystal state is disclosed. The organic semiconductor layer is formed from an organic semiconductor material including a liquid crystal molecule. The semiconductor material has properties capable of exhibiting a supercooled state during a phase transition process, in which a phase having no periodic regularity is capable of being transferred into a phase having periodic regularity at a location of a center of gravity in between the liquid crystal molecules. The phase having no periodic regularity at a location of a center of gravity In between the liquid crystal molecules is a nematic liquid crystal phase and the phase having periodic regularity at a location of a center of gravity in between the liquid crystal molecules is a crystal phase.