Provided is a highly palatable and safe glucosyltransferase inhibitor or anti-dental caries agent. A glucosyltransferase inhibitor or anti-dental caries agent having an epigallocatechin gallate polymer or a salt thereof. Particularly, the above agent containing an epigallocatechin gallate polymer, which is a compound in which chroman rings are bonded at position 6 and/or 8 via a methylene group.