An 8-azaprostaglandin represented by formula (I) (wherein all symbols have the same meanings as described in the specification), a pharmaceutically acceptable salt thereof or a cyclodextrin clathrate thereof. Since the compound represented by formula (I) binds to EP2 subtype among PGE receptor strongly, it is useful for preventive and/or treatment for immune diseases, allergic diseases, neuronal cell death, dysmenorrhea, premature birth, abortion, baldness, retinal neuropathy such as glaucoma, erectile dysfunction, arthritis, pulmonary injury, pulmonary fibrosis, pulmonary emphysema, bronchitis, chronic obstructive pulmonary disease, hepatic injury, acute hepatitis, liver cirrhosis, shock, nephritis, renal failure, circulatory diseases, systemic inflammatory response syndrome, sepsis, hemophagocytosis syndrome, macrophage activation syndrome, still disease, Kawasaki Disease, burn, systemic granuloma, ulcerative colitis, Crohn disease, hypercytokinemia at dialysis, multiple organ failure, or bone diseases etc.