To provide: an oral pharmaceutical composition that contains fine particles of a tyrosine kinase inhibitor, where the particles of the tyrosine kinase inhibitor can stably retain the fine particle state even under an intragastric environment； and a manufacturing method thereof.SOLUTION: An oral pharmaceutical composition comprises particles of a tyrosine kinase inhibitor having an average particle diameter from 50 nm to 400 nm inclusive, and a dispersant which is at least one selected from the group consisting of hydroxypropyl methylcellulose and methylcellulose and contained in an amount from 1 mass% to 100 mass% based on the total mass of the particles of the tyrosine kinase inhibitor. Also provided is a manufacturing method thereof.SELECTED DRAWING: None【課題】微細なチロシンキナーゼ阻害剤の粒子を含み、かつ、そのチロシンキナーゼ阻害剤の粒子が、胃内環境下においても、微細な状態を安定に保持し得る経口用医薬組成物及びその製造方法の提供。【解決手段】平均粒子径が５０ｎｍ以上４００ｎｍ以下のチロシンキナーゼ阻害剤の粒子と、ヒドロキシプロピルメチルセルロース及びメチルセルロースからなる群より選ばれる少なくとも１種であり、かつ、チロシンキナーゼ阻害剤の粒子の全質量に対して１質量％以上１００質量％以下である分散剤と、を含む経口用医薬組成物及びその製造方法。【選択図】なし
