A photoreceptor protein-based spectrophotometer may include a field-effect transistor and a photoreceptor protein on the field-effect transistor (FET), the photoreceptor protein exhibiting change in electrical properties by absorbing light and being activated. Since the spectrophotometer can convert the light absorbed by the photoreceptor protein to an electrical signal using the FET, it can mimic human vision by using human photoreceptor proteins. The spectrophotometer can measure the color, intensity, etc. of light of broad wavelength ranges as in human vision. Thus, the spectrophotometer can be applied to the development of artificial vision, etc.