In situ orientation of the three planes of anisotropy in granite was at first investigated with the empirical aid of quarrymen at twenty-six quarries in the Inland Sea area in Western Japan. The azimuthal variation of the sound velocity was measured and the feature of the cracks was investigated on thin sections of the rock with an optical microscope. The defects were classified into open cracks, healed cracks and other defects for every rock. In the specimens from almost all of the quarries, the rift plane consists of open cracks within the quartz's grains and the strikes are nearly parallel to the horizontal plane. Thus the grain plane and the hardway plane is vertical. The grain plane consists of open cracks and/or healed ones within the quartz, while the hardway plane consists of a few cracks within the quartz but often consists of healed cracks within the feldspar grain.