Provided is a stable pharmaceutical composition, comprising an anti-human TSLP receptor antibody, capable of inhibiting the generation of chemically modified substances, such as deamidated forms and oxidized forms, or decomposition products or multimers. The pharmaceutical composition comprises an anti-human TSLP receptor antibody, a pharmaceutically acceptable buffer, arginine or a pharmaceutically acceptable salt thereof, and a surfactant.提供抑制脫醯胺體或氧化體等化學修飾體、或分解物或多聚體之生成而成的含有安定之抗人類TSLP受體抗體而成的醫藥組成物。前述醫藥組成物,係含有抗人類TSLP受體抗體、製藥學上所容許之緩衝劑、精胺酸或其製藥學上所容許之鹽、及界面活性劑而成。