Distribution of radioactive 134Cs due to the Fukushima Dai-ichi Nuclear Power Plant accident was measured using a scintillation spectrometer in the mountainous areas of southern part of the Tohoku, northern and southern parts of Kanto and Koshin-etsu regions. As a result, intensity of radiation increased with decrease of altitude in Mt. Azuma and Mt. Yamizo, whereas intensity increased with increase of altitude in Mt. Gozen and Mt. Oyama. This indicates that plumes (polluted air masses) with their center at the specific height moved depending on the meteorological condition. Although radioactive 134Cs was not detected at Mt.Kaikoma, relatively intense γ-ray was observed due to radioactive 40K from granite.