A flaked, ground, and waisted axe, discovered on Iriomote Island in the Yaeyama group, southernmost Japan, appears to be a unique find in Japanese prehistory. Its resemblance to waisted, edge-ground axes which, in Australia, are of Pleistocene age, and to similar artifacts of early Holocene age in New Guinea, as well as potential antecedents in the Pleistocene edge-ground axes of Honshu, invites questions about its significance. This is especially so because the Yaeyama Islands are regarded currently as having been first occupied by people during the Shimotabaru phase of Neolithic culture, beginning about 3800 B.P. Comparison with similar western Pacific artifacts, and consideration of the eustatic history of the Yaeyamas, suggest that the Iriomote example might be of early Holocene age, although its origin within the late Holocene cannot be excluded. The find raises questions about the human history of the southern Ryukyu groups that demand further research.