So far a few papers have been described microscopic variation of shear plane in order to clarify shear failure of soil, it is difficult, however, to find any paper that expresses behaviours of soil particles after shear failure. In this paper, the behaviours of particles composed of the quartz crystal within a range of resolving power in optical microscope are produced by shear failure to develop results of the previous studies. Specimens were sheared to find microscopic variation in them as shear strain increased at four different stages, 2.5%, 5%, 10% and 20% respectively under strain rate at 1mm/min, after they had been compressed in shear box under normal stress for thirty minutes and remained in the same condition. Thin section used for microscopic observation were prepared with the method in which 60% solution of U-Loid 120 (epoxy resin specially made for gelling time due to time of shear completion at each strain percent) was poured before compression. Two dimensional distribution of microscopic variation in sheared specimens and soil particles can be said below from the direct observation of thin section of which has normal section to shear plane in the crossed Nicol, and also from the results of light intensity measurement through the thin section. The disturbed portion of soil particles caused by increment remarkable variation occur in specimen after shear strain reaches 5% which gives maximum shear stress. Namely, from initial point of shear behaviours of soil particles cause discontinuity radially under the condition of 5% and below of shear strain, and then distribution of particles is random orientation. Crack perhaps caused by shear failure happens and particles rise up around the crack almost in certain direction, and especially particles at the edge of crack flow remarkably. This crack grows rapidly after shear strain exceed 10% and forms disturbed zone all over the forced shear plane. This disturbed portion, however, may be restricted within narrow area at both sides of crack and then in this limited area particles may be laid out in parallel to this crack. The assumed flow of observed particles does not exist at both sides of upper and lower parts of specimen but stays in area of 5 mm from upper and lower parts of forced shear plane. Phenomenon of shear failure mentioned above is shown in Fig. 4-8 and summarized in Fig. 9. There are pleochriosm for quartz crystal in thin section, therefore it is necessary to reconsider in use of Eq. (5) induced from non-absorbing theory.