A new species of tubulanid palaeonemertean, Tubulanus izuensis sp. nov., is described as the sixth member of the genus in Japanese waters, based on materials dredged at depths of 244–436 m. It can be differentiated from all the known congeners by the unique burnt-orange dorsal pattern consisting of a median longitudinal stripe and transverse bands on a white ground color. In a maximum-likelihood tree reconstructed with partial sequences of the 16S rRNA, cytochrome c oxidase subunit I, 18S rRNA, 28S rRNA, and histone H3 genes, Tubulanus was not monophyletic, while T. izuensis sp. nov. was more closely related to the type species T. polymorphusRenier, 1804 than some other congeners including T. punctatus (Takakura, 1898), T. rhabdotusCorrêa, 1954, T. sexlineatus (Griffin, 1898), and T. tamiasKajihara, Kakui, Yamasaki & Hiruta, 2015.