PROBLEM TO BE SOLVED : To provide an oral pharmaceutical composition, particularly a tablet quickly disintegrating in the oral cavity having a less decrease in hardness even after stored under high humidity conditions and excellent hardness and disintegration properties. SOLUTION : There is provided an oral pharmaceutical composition which comprises a pharmaceutically active ingredient or a pharmaceutically acceptable salt thereof, one or more additives selected from a sugar or a sugar alcohol and a disintegrator, wherein the pharmaceutically active ingredient or a pharmaceutically acceptable salt thereof preferably is galantamine or a salt thereof, more preferably galantamine hydrobromide, the sugar or the sugar alcohol preferably is one or more selected from mannitol, trehalose, xylitol, erythritol, lactose, glucose and sucrose, preferably mannitol and the disintegrator is carmellose. SELECTED DRAWING : None COPYRIGHT : (C)2019, JPO&INPIT