Provided is an outermost layer coating composition for forming a film having a thickness not exceeding 100 µm as the outermost layer on an orally disintegrating tablet, said composition being characterized by including trehalose and/or erythritol, and also including at least one type of water-insoluble inorganic compound selected from the group consisting of water-insoluble inorganic salts, silicic acid compounds, aluminum hydroxide, magnesium oxide, and zinc oxide, each having an average particle size of 0.1 to 50 µm, and/or a water-insoluble fatty acid or a salt or ester thereof. This outermost layer coating composition allows for coated tablets that retain the contradictory characteristics required of orally disintegrating tablets, namely hardness and rapid disintegration, while also ensuring a hard-to-crack smooth surface even if the coating film is thin.
