To provide a photoconductor which operate at a high rate.

The photoconductor comprises an InP substrate 10, a first conductive contact layer 20 formed on the InP substrate 10, a photoconductive layer 22 formed on the first conductive contact layer 20 and exhibiting conductivity only when light impinges thereon, and a second conductive contact layer 24 wherein a protective film 30 is formed in a through hole 26 made through the second contact layer 24. Electrodes 42, 44 are provided, respectively, on the first and second contact layers 20, 24. Incident light is received by the photoconductive layer 22 through the protective film 30 and the photoconductor 1 detects incidence of light when a current flows between the electrodes 42, 44. Thickness of the photoconductive layer 22 represents the distance between the electrodes 42, 44. Since the photoconductive layer 22 is grown epitaxially, thickness thereof can be controlled on the order of nanometer thus realizing a photoconductor which can operate at a high rate.