Eight species of digenean trematodes of the families Fellodistomidae, Opecoelidae and Hemiuridae including a new species, were recorded from anguilliform and gadiform fishes caught in deep-sea area of Tosa Bay, off the Pacific coast of southern Japan. A new species, Plagioporus katadara (Opecoelidae) was proposed based on materials from Gadomus colletti (Macrouridae). In addition, the author included four unidentified materials, which were still remained as generic level, mainly due to that number of materials obtained had been too small.