An object of the present invention is to develop and provide a method for efficiently and simply producing a nucleic acid aptamer having high specificity and binding property to a target substance, particularly a DNA aptamer. A single-stranded nucleic acid library and a target substance are mixed in a solution, a complex forming step for forming a complex of a single-stranded nucleic acid and a target substance, a solution after the previous step and a solid phase carrier are mixed, An immobilization step of immobilizing the complex to the solid phase carrier via a target substance and / or a binder adsorbed to the solid phase carrier, a recovery step of recovering the complex immobilized on the solid phase carrier from the solution, a complex A single-stranded nucleic acid that forms an intramolecular three-dimensional structure after a single-stranded nucleic acid obtained by collecting the single-stranded nucleic acid in the body and then amplifying the nucleic acid by the nucleic acid amplification method. A method for producing a nucleic acid aptamer including a preparation step is provided.標的物質との特異性及び結合性が高い核酸アプタマー、特にDNAアプタマーを効率的、かつ簡便に製造する方法を開発し、提供することを目的とする。一本鎖核酸ライブラリーと標的物質とを溶液中で混合して、一本鎖核酸と標的物質の複合体を形成させる複合体形成工程、前工程後の溶液と固相担体を混合して、標的物質及び／又は固相担体に吸着させた結合子を介して複合体を固相担体に固定化する固定化工程、固相担体に固定化された複合体を溶液から回収する回収工程、複合体中の一本鎖核酸を回収後、核酸増幅法によって増幅させる増幅工程、及び増幅工程で得られた二本鎖核酸を一本鎖化した後、分子内立体構造を形成させる一本鎖核酸調製工程を含む核酸アプタマーの製造方法を提供する。
