[en] We compiled 62 in-situ stress data (21 boreholes by deformation methods and 41 boreholes by bottom surface methods), measured to a depth over 100 m in Japan. This data served as a basis to study the deep underground stress states in the country. Results indicate that the stress states in igneous, sedimentary, and metamorphic rocks were different from each other. Large horizontal stresses, which were twice larger than vertical stresses, were measured in many sites of igneous rocks. The directions of the maximum horizontal stresses did not always coincide with those of the maximum axes of crustal strain change obtained by geodetic triangle measurements between 1994 and 1985. (author)