In an organic photodiode, in a gap between a transparent anode formed on a glass substrate, and a reflection cathode formed oppositely thereto, a plurality of light receiving parts as layers of light absorbing composition, and partition walls for insulating between transparent anode and reflection cathode and insulating between adjacent light receiving parts are formed. Partition walls are formed by applying an ink solution to transparent anode and an insulating layer covering its periphery, dissolving the insulating layer by an organic solvent contained in the ink solution, and forming a plurality of dissolved holes contacting with transparent anode. The plurality of light receiving parts are formed by filling the plurality of dissolved holes with the light absorbing composition contained in the ink solution.