We examined the distribution and feeding habits of the diel vertical migratory myctophid Myctophum orientale in the Kuroshio region of the western North Pacific in late winter. All 1985 specimens collected were in the juvenile stage, with a mean standard length (SL) of 29.9 mm. They occurred on the onshore side of the Kuroshio axis along the slope region off Japan, showing a typical pseudoceanic distribution. Juveniles <35 mm SL depended heavily on appendicularians, while juveniles ≥35 mm SL preyed on various species of copepods (predominantly Candacia bipinnata) and euphausiid calyptopis and furcilia stages. Based on estimated biomass (2.85 mg m-3) and nighttime ration (10.5–13.8% of body weight d-1), the predatory impacts of M. orientale on the biomass and production rate of the mesozooplankton were calculated to be 0.3–0.8% and 6.0–15.5%, respectively, in the surface layer. In the study area, M. orientale co-occurs with larvae and juveniles of Japanese sardine and mackerels, both of which also prey on appendicularians. Predatory impacts of M. orientale <35 mm SL on the biomass and production rate of appendicularians were estimated to be 2.5–7.4% and 4.7–14.1%, respectively. This suggests that M. orientale is a competitor for prey with the small pelagic fish on the onshore side of the Kuroshio axis during late winter.