The determination of radium was made by the solution method, using the ionization chamber. The samples were collected from six granite bodies in Kyushu: Tsushima, Okue-yama, Ichifusa-yama, Shibisan, Takakuma-yama, and Osumi granite bodies.<br> All of these bodies, which are composed exclusively of fine-grained biotite granite containing dark or light brownish-red or reddish-brown zircons, are intruded into Paleozoic or Mesozoic sediments accompanied by both thermo-metamorphic effect and pneumatolytic ore deposits on their north or south side, showing small circular exposures from 4 to 10km in diameter.<br> As regards radium content, the Tertiary granites investigated are distinguished from older granites by the following characters:<br> (1) The Tertiary granites are richer in radium than older ones; (2) The mean radium content of each Tertiary or Cretaceous granite body generally increases with increasing silica, while that of each Permo Triassic Ryoke granite body tends to decrease; (3) As to an individual granite body, the radium content of Cretaceous granite varies sympothetically with silica, but that of the Ryoke granite is in antipathetic relation to silica. Such relations between radium and silica contents cannot clearly been perceived in any Tertiary granite body, because there observed little variation of silica if present; (4) The orders of intrusion of the Ryoke and Cretaceous granites have been known well: the former granite shows the tendency that radium is more concentrated in younger intrusions, while the latter in the older. In the case of the Tertiary granites, however, the order of intrusion has not yet been decided.