Dynamic shearing properties of rock discontinuities are of great importance in many rock engineering applications. Nevertheless, dynamic shear tests on rock discontinuities are very rare. In this study, the authors describe two-ways shearing experiments on various natural rock discontinuities and saw-cut planes. Natural rock discontinuities involve schistosity planes in quartzite, green-schist, cooling planes in andesite, saw-cut planes of Ryukyu limestone, Motobu limestone, andesite and basalt from Mt. Fuji, dolomite from Kita-Daitojima, grano-diorite from Ishigaki and Inada granite. Furthermore, these experimental results are compared with those from static and one-way dynamic shearing experiments and their implications in practice are discussed.