A nucleic acid extraction device so constituted as to extract nucleic acid by moving a nucleic acid-containing solution, by providing a plurality of tanks on a rotating disk, connecting each tank to each other with a flow path provided with an open/close mechanism, and sequentially separate and extract specified components from solutions in respective tanks. An automatic treating by means of a plurality of tanks connected with open/close mechanism-carrying flow paths can treat an aqueous solution containing a large amount of nucleic acid with no foreign matters mixed in to ensure high-sensivity, high-accuracy extraction of nucleic acid and reduce nucleic acid extracting cost and time.
