When using an immunological analysis method wherein antigen-antibody reactions are used to form complexes of microparticles and a substance being measured, purifying, then measuring by spectroscopy, and a mass spectrometry method wherein antigen-antibody reactions are used to form complexes of microparticles and a substance being measured, purifying, then measuring with a mass spectrometer, the amount of the complex flowing in the flow path for immunological analysis and the amount of the complex flowing in the flow path for mass spectrometry are unknown, so the substance being measured cannot be accurately quantified even when merging information obtained from immunological analysis and information obtained from mass spectrometry. The invention provides a mechanism for quantifying the complexes after formation of the complexes, on the flow path for mass spectrometry and the flow path for immunological analysis.