PROBLEM TO BE SOLVED: To provide a pharmaceutical composition for oral or parenteral administration in order to use in the treatment and prevention of retroviral diseases and mycobacterial infection, the composition comprising calanolide and having high solubility and bioavailability; and to provide a preparation method thereof.SOLUTION: The invention provides a pharmaceutical composition of calanolide for oral or parenteral administration having high solubility and bioavailability, wherein a) calanolide or a mixture of calanolide(s), b) one or more solubility improvers, and c) one or more surfactants are comprised, the solubility improver is an oil, and the surfactant is a nonionic surfactant; and a preparation method thereof.SELECTED DRAWING: Figure 1【課題】レトロウイルス疾患及びマイコバクテリア感染症の治療及び予防に用いる、カラノライドを含む経口又は非経口投与用の高い溶解度及び生物学的利用能を有する医薬組成物及びその調整方法。【解決手段】a)カラノライド又はカラノライド(複数)の混合物、b)1つ又は複数の溶解度向上剤、及びc)1つ又は複数の界面活性剤を含み、前記溶解度向上剤が、油であり、前記界面活性剤が、非イオン性界面活性剤である、高い溶解度及び生物学的利用能を有する経口又は非経口投与用のカラノライドの医薬組成物及びその調整方法。【選択図】図1