Providing an organic thin-film solar cell that can be easily manufactured and then mass produced at low cost while increasing the photoelectric conversion efficiency, and the method of producing the same.Solar cells 100-102 include at least one of a mixed P-type organic semiconductor layer 12M and a mixed N-type organic semiconductor layer 14M. A plurality of organic semiconductor materials are mixed in the mixed P-type organic semiconductor layer 12M or the mixed N-type organic semiconductor layer 14M, respectively. In such a way, the photoelectric conversion efficiency of the solar cells is increased by selecting and mixing proper organic semiconductor materials to form the organic semiconductor layer.