Disclosure is a method of separately recovering deoxyribonucleic acid and
ribonucleic acid from a biological sample solution. They are separated
and recovered from a single biological sample by controlling pH values,
temperature, and/or concentration of cationic ions of a nucleic acid
sample solution containing a caotropic agent. It is possible to easily
and safely separate and recover deoxyribonucleic acid and ribonucleic
acid from the single biological sample.