To prolong recombination time of quasiparticles of superconductor which are generated by irradiation of a light, by forming a light detecting part of laminated films in which high temperature superconductor thin films and ferromagnetic thin films are laminated via insulating thin films.

SrTiO3 (001) single crystal is used for a substrate 14. The respective targets of YBa2Cu3O7-x SrTiO3, La0.9Sr0.1MnO3 which are formed by using a solid-phase reaction method are alternately irradiated with a laser. A desired number of layers of oxide superconductor thin films YBa2Cu307-x 11 and oxide ferromagnetic thin films La0.9Sr0.1MnO3 12 are laminated via oxide insulator thin films SrTiO3 13. Thus, a light detecting part is constituted. Film thicknesses of the layers are made about 20 nm, 10 nm, and 5 nm, respectively. A superconductor thin film/a ferromagnetic thin film are made one unit, and 10 units of laminated films are formed, in all. After that, protection is performed by using photoresist (AZ-1518). A part which is not protected is eliminated with an Ar ion beam, and work into the light detecting shape is performed.