Floristic research of marine benthic cyanobacteria was made in the coast around the Kanto District in Japan. As a result, we recognized 27 species, and among then, Placoma adriatica, Placoma micrococcum, Placoma sp., Coleofasciculs chthonoplastes, Caldora penicillata, Symploca meneghiniana,Lyngbya confervoides, Lyngbya semiplena, Phormidium holdenii, Phormidium nigroviride, Scytonematopsis pilosa. Symploca meneghiniana is newly recorded in Japan
