Using an optical electric field enhancing device including a fine uneven structure made of gold formed on the front surface of a transparent substrate, illumination light of a wavelength in the range from 400 to 530 nm is applied at least to an analyte, positional information of the analyte is detected by a position detection unit disposed on the rear surface side of the optical electric field enhancing device, and excitation light is applied to the detected position by an excitation light application unit. Signal light emitted from the analyte when the excitation light is applied is detected from the rear surface side of the transparent substrate.