The present invention provides a dry powder pharmaceutical composition for inhalation useful as medicine preventing and treating influenza virus infectious disease.This dry powder pharmaceutical composition for inhalation may contain the compound of the formula(I)in addition with the compound of the formula (II), the pharmaceutically acceptable salts or these hydrates as the active ingredient.本發明提供作為流行性感冒病毒感染症之預防及/或治療有用之吸入用乾燥粉末醫藥組成物。含有以如化合物[如下式(I)化合物,更可包括如下式(II)化合物]、其藥理容許鹽、或彼等之水合物為藥效成分之吸入用乾燥粉末醫藥組成物。