PROBLEM TO BE SOLVED: To provide an enzyme activity inhibitor derived from intraoral bacteria which can effectively inhibit an enzymatic activity derived from intraoral bacteria, can effectively adsorb or bond a component inhibiting the enzyme activity, to oral mucosa, and can secure a good intraoral environment.SOLUTION: The invention relates to an enzyme activity inhibitor derived from intraoral bacteria which contains, as active ingredients, (A) oryzanol, and (B) one or more kinds of oil solutions selected from triacylglycerol (b1), tocopherol (b2), and hydrocarbon oil (b3) which are liquid at 25°C, and wherein the mass ratio ((B)/(A)) of a component (A) and a component (B) is 0.8 or more to 20 or less.
