Object: To provide a biochip for use in exhaustive analysis of a particular protein including DNA (deoxyribose nucleic acid) in a body fluid through Raman quantitative analysis.Resolving Means: Aqueous solution of metal complexes including plasmon metal selected from the group consisting of Au, Ag, Pt and Pd is supplied dropwise onto a carrier metal having an electrode potential of metal less noble than complex metal, followed by precipitation of nanometric quantum crystals from the metal complex on the carrier metal, the metal complex being so selected as to have a complex stability constant (log β) that is expressed by the following equation (I) correlating with the electrode potential E of the carrier metal: E°=(RT/|Z|·F)In(βi)  (I) (wherein E° represents the standard electrode potential, R represents a gas constant, T represents the absolute temperature, Z represents the ion valency, and F represents the Faraday constant), the surface property of the metal complex quantum crystals on the carrier metal being subsequently adjusted in dependence on an object to be detected in the aqueous solution prior to the precipitation or after the precipitation.