The present invention provides an organic semiconductor device comprising an organic semiconductor layer having good charge carrier transport property, wherein a carrier injection to the organic semiconductor layer is easy. The above problem is solved by an organic semiconductor device comprising a first electrode and a second electrode facing to each other, and an organic semiconductor layer provided in between the first electrode and the second electrode, wherein a charge carrier injection promoting layer is formed in between the organic semiconductor layer and at least one electrode of the first electrode and the second electrode.