The present invention pertains to an enzymatic measurement method using an antibody-enzyme complex or a nucleic acid probe measurement method using an enzyme-labeled nucleic acid probe, in both of which the quantification of a product of a reaction by an enzyme in the antibody-enzyme complex or the enzyme-labeled nucleic acid probe is performed by generating thio-NAD(P)H by an enzymatic cycling reaction using NAD(P)H, thio-NAD(P), and a dehydrogenase (DH), and measuring the amount of the generated thio-NAD(P)H or measuring a change in color caused by the generated thio-NAD(P)H. An enzymatic reaction system in which NAD(P) generated from NAD(P)H by the enzymatic cycling reaction is selectively reduced, is caused to coexist with the enzymatic cycling reaction. The present invention also pertains to a kit for enzyme immunoassay, and a kit for nucleic acid probe measurement. In the enzymatic cycling reaction, the detection sensitivity is increased by increasing the amount of thio-NAD(P)H generated per unit time with respect to a predetermined amount of a substrate (reduced), and combining the same with an enzyme immunoassay, etc., enables quantification, etc., of a protein or nucleic acid with high sensitivity.