Me-akan volcano on the volcanic front of Kurile arc, eastern Hokkaido, has grown on the Akan caldera and its activity can be divided into three stages, i. e. (1) stage-I characterized by the formation of four tratovolcanoes ; 1042 m-peak, Minami-dake, Nakamachineshiri, and Higashi-dake, (2) stage-II by major pumice-scoria eruptions at 13520±240 BP, resulting in the formation of Nakamachineshiri-somma, and (3) Stage-III by the formation of andesitic volcanoes of Nakamachineshiri-dome, Kitayama and Ponmachineshiri, and of two basaltic volcanoes of Nishiyama and Akanfuji. The petrography, mineralogy, and geochemistry of Me-Akan rocks are described. Two major types of plagioclase phenocrysts (types-A and -B) are recognized : type-A plagioclase contains black glass inclusions and was originally derived from tholeiitic mafic magmas, while type-B plagioclase has colorless inclusions and was derived from calc-alkaline dacite magmas. Basalts and basaltic andesites show mineralogical evidence of magma mixing. Oscillatory or two-stage reverse zoning in type-A plagioclase and augite phenocrysts and reversely-zoned overgrowth of augite on resorbed orthopyroxene phenocryst suggest that the phenocrysts in the basaltic rocks preserve a record of multi-stage internal mixing of tholeiitic magmas in magma chambers. However, notable difference in Rb/Zr ratio is found in these basaltic rocks, which indicates that parental magmas with different chemical compositions were probably injected into respective magma chambers beneath Akanfuji, Nishiyama and Minami-dake. During the somma-building activity of stage-II, simultaneous eruptions of andesite, dacite, and basaltic andesite magmas took place. Morphological and petrological analyses and recent fluid dynamical experiments suggest that the turbulent flow of basaltic andesite magma, supplied from lower layer of a zoned magma chamber, ascended rapidly in the central part of the conduit, and incorporated it with dacite magma to form heterogeneous and hybrid magmas. Since andesitic lavas contain both type-A and type-B plagioclase phenocrysts, they may have been formed by circulated mixing in a conduit between tholeiitic mafic magmas and calc-alkaline dacite magmas which had previously undergone mixing in zoned magma chambers. The calc-alkaline dacites show high Rb/Zr ratios (0.31-0.36) and relatively low FeO^*/MgO ratios (2.0-2.3), which suggests that the dacite magmas may not be produced by fractional crystallization of the tholeiitic magmas but by partial melting of the lower crust.