1. A method of collecting a nucleic acid from a biological sample, comprising
the steps of:
a) mixing a support comprising a water-soluble neutral polymer adsorbed on a cerium oxide surface thereof with a solution containing a nucleic acid to adsorb the nucleic acid to the support,
b) separating the support on which the nucleic acid was adsorbed from the solution mixed in the step a), and
c) collecting the nucleic acid by adding an eluent to the support on which the nucleic acid was adsorbed and which is separated in the step b).

2. The method of collecting a nucleic acid according to claim 1, wherein the water-soluble neutral polymer is a polymer with a zeta potential of not less than -10 mV and not more than +10 mV in a solution of pH 7.
3. The method of collecting a nucleic acid according to claim 1 or 2, wherein the polymer is polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, poly(2-ethyl-2-oxazoline), polypropylene glycol, polyacrylamide, poly(N-isopropylacrylamide) or hydroxypropylmethylcellulose.
4. The method of collecting a nucleic acid according to any one of claims 1 to 3, wherein the eluent is a buffer solution.
5. The method of collecting a nucleic acid according to any one of claims 1 to 4, wherein the biological sample is blood, urine, saliva, a mucous membrane, sweat, a cultured cell, a culture liquid of cultured cells, a tissue sample, a specimen, a microorganism, a culture liquid of a microorganism or a virus.
6. A support comprising a water-soluble neutral polymer adsorbed on a cerium oxide surface thereof.
7. The support according to claim 6, wherein the water-soluble neutral polymer is a polymer with a zeta potential of not less than -10 mV and not more than +10 mV

in a solution of pH 7.
8. The support according to claim 6 or 7, wherein the water-soluble neutral polymer is polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, poly(2-ethyl-2-oxazoline), polypropylene glycol, polyacrylamide, poly(N-isopropylacrylamide) or hydroxypropylmethylcellulose.
9. A kit for collecting a nucleic acid, comprising the support according to any one of claims 6 to 8 and a buffer solution.