A polypeptide of N-acetylglucosamine-6-O-sulfotransferase and a DNA encoding the peptide are provided. The polypeptide is (a) or (b) below: (a) a polypeptide having the amino acid sequence represented by SEQ ID NO: 2; or (b) a polypeptide which includes an amino acid sequence including substitution, deletion, insertion or transposition of one or a few amino acids in the amino acid sequence of (a) and which has an enzymatic activity to transfer a sulfate group from a sulfate group donor to a hydroxyl group at 6 position of an N-acetylglucosamine residue located at a non-reducing end of an oligosaccharide represented the formula I: GlcNAcβ1-3Galβ1-4GlcNAc  (I) where GlcNAc represents an N-acetyl-glucosamine residue, Gal represents a galactose residue, β 1-3 represents a β 1-3 glycosidic linkage, and β 1-4 represents a β 1-4 glycosidic linkage.