<Synopsis>The hermit beetle, Osmoderma opicum Lewis, 1887 is one of the endangered beetle species living in tree hollows. We found the beetle in a warm-temperate evergreen forest on Mt. Kasugayama. This beetle has been thought inhabiting a summergreen forest zone and the coniferous trees zone of the high altitude. Therefore, it was the first time to prove that the beetle can inhabits in a warm-temperate evergreen forest.