A metal layer 13 made of Au or the like is formed on the upper surface of a transparent substrate 12. Dielectric layers 14a, 14b and 14c with different thicknesses are formed on the upper surface of the metal layer 13 (any one of the dielectric layers can have a thickness of 0) to form respective determination areas 15a, 15b and 15c. Further, different types of antibodies 22a, 22b and 22c are fixed on the upper surfaces of the respective dielectric layers 14a, 14b and 14c. Then, light is directed to the determination areas 15a, 15b and 15c, then signals of light reflected by the determination areas 15a, 15b and 15c are received, the light is dispersed, and analyses are performed on signals resulted from the light dispersion to detect the conditions of the surfaces of the respective determination areas, at the same time.