Abstract: An immunological assay method, wherein the concentration of a substance to be assayed is calculated from a calibration curve, which is formed in the preparation of a reagent or in the assay of a sample based on parameter(s) determined in the preparation of the reagent, without the need of forming any additional calibration curve each time, is disclosed. By the immunological assay method of the present invention, the concentration of the substance to be assayed can be efficiently and discontinuously determined, when compared with conventional ones. The method of the present invention is particularly suitable for quantitatively determining an antigen or an antibody.