A method for separating and purifying nucleic acid, the method comprising: (1) a step of contacting a sample solution containing nucleic acid with a solid phase to adsorb the nucleic acid on the solid phase; (2) a step of contacting a washing solution with the solid phase to wash the solid phase in a state that the nucleic acid is adsorbed on the solid phase; and (3) a step of contacting a recovering solution with the solid phase to desorb the nucleic acid from the solid phase, wherein the sample solution is prepared by including a step of removing a precipitate component, and adding a surfactant and a water-soluble organic solvent to a supernatant solution of the precipitate.