A self-assembling peptide containing a polar amino acid residue and a nonpolar amino acid residue, wherein the self-assembling peptide contains an acidic amino acid residue and a basic amino acid residue as the polar amino acid residues, a total sum of charge of the acidic amino acid residue and charge of the basic amino acid residue in a neutral region is the number excluding 0, and the self-assembling peptide is capable of forming a beta (β)-sheet structure in which only the nonpolar amino acid residue is arranged on one face upon self-assembly in an aqueous solution.
