The problem of the present invention is to provide a protein hydrophilicity-increasing agent capable of effectively increasing water permeability of (swelling) hair, skin and the like while suppressing damages on the hair, skin and the like constituted of the protein.The present invention solves the problem by providing a protein hydrophilicity-increasing agent containing a protein-glutaminase, and a protein hydrophilicity-increasing agent containing both a protein-glutaminase and transglutaminase.
