We examined predation of the forest green tree frog, Zhangixalus arboreus, as part of a two-year monitoring study of the frog's reproductive processes at four ponds in central Japan, performed by using field censuses and sensor cameras. During the period, we confirmed predation against arboreal foam nests by the common raccoon, Procyon lotor. We also found a carcass of a female adult frog with eggs and bitten ground foam nests, the signs of which were strongly suspected to indicate predation by raccoons. These results imply that invasion of Japanese forest areas by alien raccoons is becoming an increasingly serious threat to Z. arboreus through predation at various life stages of the frog. At this study site, however, the demographics of both the raccoon and Z. arboreus have not yet been examined. We need more field data to assess the long-term effects of predation pressure on the frog.