Paleozoic and Mesozoic radiolarians were recovered from the Jurassic accretionary complex of the Chichibu Belt in the Iragomisaki district, Atsumi Peninsula, Aichi Prefecture, Southwest Japan. Permian and Triassic radiolarians were detected from 7 and 23 samples of chert, respectively. Jurassic radiolarians were obtained from 10, 6 and 11 samples of chert, siliceous mudstone and mudstone, respectively. 108 species belonging to 54 genera are identified, and are shown in plates with undescribed morphotypes as a database for further study. Based on Permian, Triassic and Jurassic radiolarian biostratigraphic schemes, the geologic ages of the examined chert, siliceous mudstone and mudstone samples range from Middle Permian to late Middle Jurassic, early Middle Jurassic to middle Middle Jurassic and early Middle Jurassic to late Middle Jurassic, respectively.