PROBLEM TO BE SOLVED: To provide a biochip capable of performing highly sensitive detection, and arraying antibodies for recognizing a target specifically on the chip surface with high density, and to provide a kit for antigen-antibody reaction detection, and a detection method for an antigen-antibody reaction. SOLUTION: This biochip (1) includes a base substrate (2) having a cyclic structure on the surface, a metal layer (4) formed on the cyclic structure, an extinction suppression layer (6) formed on the metal layer (4), and a bispecific antibodies (7) bonded on the extinction suppression layer (6). The metal layer (4) is formed of a metal capable of generating surface plasmon resonance light, and the extinction suppression layer (6) is formed of zinc oxide (ZnO), and the bispecific antibody (7) is an antibody whose one end recognizes zinc oxide, and whose other end recognizes a fluorescence labeled protein, and light is allowed to enter to generate an electric field enhanced by the surface plasmon resonance light, and enhanced fluorescence is detected by using the generated electric field as an excitation field of the fluorescence labeled protein. COPYRIGHT: (C)2011,JPO&INPIT