An object of the present invention is to solve inhibition of biopolymer measurement in a nanopore, which involves three-dimensional conformation of a biopolymer containing a nucleic acid. The present invention provides a device for analyzing a biopolymer containing a nucleic acid, the device including: an array device including a plurality of thin film parts having a nanopore; a single common container and a plurality of individual containers capable of storing a measurement solution which is brought into contact with the thin films; and individual electrodes respectively provided in the plurality of individual containers, wherein: the measurement solution is introduced into each of the individual containers and the common container so as to be brought into contact with the thin films; and the measurement solution has a pH equal to or greater than pKa of a guanine base and contains cesium ions as electrolyte cations.