The present invention relates to an organic semiconductor material in which carbon nanotubes are dispersed in a conjugated polymer, and the weight fraction of the carbon nanotubes is 3 percent or less relative to the conjugated polymer. According to the present invention, an organic semiconductor material having a high carrier mobility can be supplied industrially. Furthermore, high-performance organic semiconductor devices, e.g., organic thin film transistor devices and organic photovoltaic devices, can be provided.