A thylacocephalan fauna from the upper Olenekian (Lower Triassic) Osawa Formation in the South Kitakami Belt, Northeast Japan, is described. The fauna comprises three species belonging to three genera: Ankitokazocaris bandoi Ehiro and Kato sp. nov., Kitakamicaris utatsuensis Ehiro and Kato gen. et sp. nov., and Ostenocaris sp. This is the first report of fossils belonging to the class Thylacocephala from Japan, and it expands their paleogeographic distribution. As almost all genera of Thylacocephala inhabited low-latitude areas in each relevant geological time, their occurrence from the Osawa Formation supports previous opinions that the South Kitakami Belt was located in the equatorial region during the Triassic.