PROBLEM TO BE SOLVED: To provide a skin elasticity improving material capable of improving skin elasticity.SOLUTION: In a skin elasticity improving material comprising an artificial protein (A), (A) has a polypeptide chain (Y) formed of following amino acid sequences (X) continuing as long as 2-200 and/or a following polypeptide chain (Y'), and the total number of (Y) and (Y') in (A) is 1-100, and hydrophobicity of (A) is 0.2-1.5； wherein the amino acid sequence (X) is a VPGVG sequence (2) or a GVCVP sequence (3)； and the polypeptide chain (Y') is a polypeptide chain in which 1-100 amino acids in (Y) are substituted with lysine or arginine, and the ratio of substituted amino acids {(the number substituted with lysine and/or arginine)/(the number of amino acids in (Y'))×100%} is 0.1-5%.
