[PROBLEMS] To reduce the amount of, for example, a capturing antibody to be employed without lowering detection sensitivity. At the same time, to enable the achievement of intense color development or light emission in a determination area even in the case where only a small amount of a labeled antibody is accumulated. To lower the detection limit in the sandwich method. To enlarge the dynamic range in the competition method. [MEANS FOR SOLVING PROBLEMS] A method of analyzing a test substance by an immunological analysis method by using the test substance, a support having a determination area, on which one member selected from a capturing antibody capable of binding specifically to the test substance and a capturing antigen capable of binding specifically to the test substance has been immobilized, and a labeled antibody capable of binding specifically to the test substance, wherein a label having a sensitizing effect has been immobilized on the determination area of the support.