The compressibility and drained shear characteristics of a sand under high pressures were investigated. A particular relationship was found between degree of compression, isotropic pressure and compression time, for a certain range of pressures. At a pressure higher than 300kg/sq. cm, however, the time necessary to reach 100 per cent compression was so long that it could not be attained the final stage of a long-term compression test extending over several hundred hours. The shear characteristics of the sand tested was found to be affected by the initial void ratio at a confining pressure as high as 500kg/sq. cm. It was shown that the shear characteristics of a sand under high confining pressures was significantly influenced not only by the phenomenon of grain crushing but also by the action of pore water.