[en] Quaternary volcanic products erupted from five volcanoes located in the central part of the H ida Mountain Range. These are the Kaminorouka Volcanic Rocks, the Warimodake Andesite, and eruptives from Iwagokekotani, Kumonotaira, and Washibaike volcanoes. We have determined the K-Ar ages for five lava samples collected from above volcanoes except for Washibaike Volcano. The K-Ar ages are measured for separated groundmass from the lavas. Based on the newly obtained ages, previously reported seven radiometric ages, and volcanostratigraphic data, we identify activity periods of each centers. These are: ca. 0.9 Ma for Iwagokekotani Volcano, 0.4-0.2 Ma for the Kaminorouka Volcanic Rocks, 0.3-0.1 Ma for Kumonotaira Volcano, ca. 0.3 Ma for Warimodake andesite, and 0.12-0.01 Ma for Washibaike Volcano, most of which are in the late early Pleistocene to the late Pleistocene. (author)