今回，土器型式及び胎土分析両面から検討する焼町土器の年代的位置付けを検討するため，群馬県・長野県の焼町土器及び中期中葉土器について，AMSを用いた放射性炭素同位体比の測定を行った。その結果，新巻土器・プレ焼町土器と呼ばれる古手のタイプについては，茅野市長峯遺跡の3例及び川原田遺跡の1例の較正暦年が，3370-2910calBCの年代に収斂しており，よくまとまっている。さらにまとまった年代を示す新巻タイプの3例は，共通する年代である3100-3090calBCを中心とする年代幅が含まれている可能性が高い。これは，これまでの測定データとあわせて考えると，新道式土器新期から藤内Ⅰ式（新地平編年6－7期）の年代に共通する。つぎに，典型的な焼町土器である川原田J4住の深鉢2例は，共通の測定値を示しており，較正暦年で3100-2900calBCの年代幅の中に含まれる。これらの土器は，勝坂2・3式（藤内Ⅱ式～井戸尻Ⅲ式）（新地平編年8－9期）に相当するが，勝坂3a式（新地平編年9a期）の年代に相当する可能性がある。以上のように，新巻土器・焼町土器2つのタイプの土器群の年代について，概ね把握することができた。We measured more than 10 samples of AMS radiocarbon ages of the potteries in the Jomon periods. Samples are charred -carbonaceous samples remained on the surface of deep bowls made in the Middle Jomon period. The purpose of this study is to clarify radiocarbon ages and calibrated ages of the Middle Jomon stages in Kantou region, and Tyubu region. The samples were scraped from the fragments of the deep bowls whose ceramic group were well known by archaeological study, such as the Aramaki-type, the Yakemachi-type, the Kasori-E1 type.The powdery carbon samples were treated with HCI and NaOH solutions. Samples were measured by AMS (Accelerator Mass Spectrometry) at the Beta-analistic. Isotopic fractionation was corrected by the δ ¹³C value. Radiocarbon age sub-tracted from 1950 sometimes substitutes for calendar age, but it is not strictly true. Radiocarbon age should be converted to calendar year with the 'calibration curve' : an empirical equation established by radiocarbon dating of tree-ring samples whose calendar age were known. In comparison of the Jomon culture with some other prehistoric culture in the world, it is required to indicate calendar age during which the Jomon pottery had been used. In this study, we reported the calibrated radiocarbon ages of the Aramaki-type, and Yakemachi-type pottery. The result of calibrated radiocarbon ages shows about the Aramaki-type pottery, as old type of the Yakemachi pottery, period in Tyubu region is roughly from 3100 to 3090 [cal BC]. The result of calibrated radiocarbon ages shows about the Yakemachi-type pottery, as typical the Yakemachi pottery, period in Tyubu region is roughly from 3100 to 2900 [cal BC] Time span of the Yakemachi type, as series from the Aramaki-type to the Yakemachi-type pottery, on the middle Jomon period, has estimated about 200 years.