To provide an epidermal keratinization normalizing agent which activates epidermal keratinizing cells, has an action to promote the expression of involucrin and keratin 10 of the constituting proteins of cornified envelope, and excels in safety.

The epidermal keratinization normalizing agent comprises an acidic xylooligosaccharide as an active ingredient. The acidic xylooligosaccharide has at least one uronic acid residue in the molecule as a side chain. The uronic acid is glucuronic acid or 4-O-methyl-glucuronic acid. The acidic xylooligosaccharide is obtained by "enzymatically and/or physicochemically treating a lignocellulose material to obtain a complex of a xylooligosaccharide component and a lignin component and then subjecting the complex to acid hydrolysis treatment to obtain a xylooligosaccharide mixture".