[en] Ruthenium, silver, rhenium, osmium, iridium, platinum, and gold in standard rock samples from Geological Survey of Japan, i.e. JB-1, JB-2, JG-1, and JA-1, were determined by thermal neutron activation method with a systematic chemical separation. U.S. Geological Survey standard rocks, BCR-1 and G-2, were also analyzed to obtain an information about the accuracy and precision on the method. General agreement of our results with previous values for BCR-1 and G-2 was excellent. The noble metal contents in the igneous rocks from Japanese region were approximately comparable to those in the corresponding rocks from the continental region, and showed a tendency to decrease with increasing silica contents, with weak interrelations to other major elements. (author)