provided is a method of achieving a simple , quick , and highly accurate detection and measurement of a biopolymer , and to provide a device for this purpose . to this end , a method of detecting a biopolymer utilizing two kinds of solvent phases different in property from each other , including steps of : allowing a sample biopolymer to react with a labeled probe biopolymer in the first solvent phase ; transferring a product of the reaction of the sample biopolymer with the probe biopolymer to a second solvent phase using a medium having surface activity between the two kinds of solvent phases ; and detecting the reaction product contained in the second solvent phase by use of the label .