Disclosed are gene carriers utilizing β-1,3-glucan and methods of preparing the same. The β-1,3-glucan has at least one 1,6-glucopyranoside branch and is chemically modified through periodate oxidation and reductive animation so as to impart nucleic acid-binding functional groups (for example, cationic functional groups) to at least some of the 1,6-glucopyranoside branches thereof. Triple helix β-1,3-glucan is dissolved in a polar organic solvent to form single-stranded β-1,3-glucan. By replacing, in the presence of a nucleic acid, the polar organic solvent for the solution containing the chemically modified single-stranded β-1,3-glucan by water, a complex (gene carrier) is formed in which the nucleic acid is bound to double-stranded β-1,3-glucan.