Hemipristis tanakai, a new species of snaggletooth shark (Order Carcharhiniformes, Family Hemigaleidae), is erected based on the fossil tooth specimens recovered from the Lower Oligocene of the Yamaga Formation of the Ashiya Group in Kyushu, Japan. This species was once proposed by Naoyuki Kuga in his dissertation in 1985, based on a single tooth; however, it has been considered unavailable because of its failure to meet the criteria of the International Code of Zoological Nomenclature. We reviewed this specimen, together with some additional specimens, and confirmed that it was distinguishable from existing congeners. This species is informative for the evolution of Hemipristis because it fills the gap in tooth morphology between Paleogene and Neogene species.