During the hunting seasons from November 1979 to February 1985, a total of 332 wild mammals of 7 different species were captured in Tajima province, the northern part of Hyogo Prefecture, which is known as a heavily infected area with the diploid type of Paragonimus westermani (Kerbert, 1878) Braun, 1899, and were examined for Paragonimus infections. Of all the animals examined, 2 martens, 13 raccoon dogs and 8 wild boars were positive for the lung flukes. On the basis of the morphological features of the worms and eggs obtained, the worms from 2 martens were identified as P.miyazakii Kamo, Nishida, Hatsushika et Tomimura, 1961, those from one of 13 positive raccoon dogs were identified as P.ohirai Miyazaki, 1939 and those from the remaining 12 raccoon dogs and 8 wild boars were identified as P.westermani -diploid type. The infection rates of those flukes in martens, raccoon dogs and wild boars were 6.3, 0.7, 8.6 and 9.1%, respectively. Natural infections of wild boars with adult P.westermani -diploid type were first reported. Therefore, raccoon dogs, and sometimes wild boars, may serve as the main natural definitive hosts of the diploid type of P.westermani in the area.