Kit for nucleic acid extraction, and nucleic acid extractor

Provided is a gene analysis device that includes a nucleic acid extractor part in which the possibility of cross contamination has been reduced and that has a nucleic acid amplification function and detection function. The kit for nucleic acid extraction, in which silica-coated magnetic beads are used in the presence of a chaotropic agent, is equipped with: a magnet cover part (52) which holds a magnet (44) inside and by which the magnet (44) and a reaction vessel (2) are separated from each other; a wall part (53) which covers the outside of the reaction vessel (2) so that at least some of the magnet cover part (52) is kept being held in the reaction vessel; and a wall part (53) which covers the space above the reaction vessel (2) so that at least some of the magnet cover part (52) is kept being held in the reaction vessel (2). Thus, liquids and aerosols can be prevented from flying out, and the possibility of cross contamination can be reduced.