The present invention aims to provide a wound healing agent that inhibits bacterial growth, promotes granulation tissue formation and epithelization, and minimizes foreign body reaction in the granulation tissue. The wound healing agent of the present invention contains protein (A) and water, wherein the protein (A) contains: GAGAGS (1); and an amino acid sequence (X) and/or an amino acid sequence (X'), and the total percentage of β turns and random coils in the protein (A) as determined by circular dichroism spectroscopy is 60 to 85%, and the percentage of the total number of amino acid residues in the amino acid sequences (X) and (X') is 50 to 70% of the total number of amino acid residues in the protein (A). Amino acid sequence (X): at least one amino acid sequence selected from the group consisting of VPGVG (2), GVGVP (3), and GAHGPAGPK (4). Amino acid sequence (X'): an amino acid sequence in which 1 or 2 amino acid residues in the amino acid sequence (X) are independently replaced by a lysine (K) or arginine (R) residue.