A color imaging element, a photosensor and a photoelectric transducer which use a protein and are capable of being stably used for a long time, and methods of manufacturing them are provided. A zinc-substituted cytochrome c552 is immobilized on a gold electrode with a self-assembled monolayer in between to form a blue-light photoelectric transducer. Alternatively, a cytochrome c552 is immobilized on a gold electrode with a self-assembled monolayer in between, and a fluorescent protein absorbing blue light is bonded to the cytochrome c552, thereby forming a blue-light photoelectric transducer. These photoelectric transducers each are used as a color imaging element or a blue-light photoelectric transducer of a photosensor.