Provided is a measurement method for at least one of a forward reaction substrate for a kinase, a phosphorus oxide thereof, and derivative precursors that are converted into the aforementioned substances. The measurement method includes: a step in which at least a kinase, a first nucleotide coenzyme of the kinase, and a second nucleotide coenzyme that has a different nucleoside moiety than the first nucleotide coenzyme are brought into contact with a sample and an enzymatic cycling reaction is carried out; a step in which a signal corresponding to the amount of change between the first nucleotide coenzyme and the transformed product thereof and/or between the second nucleotide coenzyme and the transformed product thereof is detected; and a step in which the amount of a forward reaction substrate for the kinase and/or a phosphorus oxide thereof included in the sample is calculated on the basis of the amount of change in the detected signal.