Microtribology of Silicon single crystals is one of the important factors for the practical use of MEMS. In this study, the effect of crystal orientation on microwear of Silicon single crystal and the wear structure were mainly investigated. Microfriction experiments using atomic force / friction force microscope (AFM / FFM) were carried out to investigate the effect of crystal orientation on the microwear depth of Silicon single crystals. In these experiments, the scanning-scratching directions of a tip of AFM / FFM were <100> and <110> on Si(100) surface and <112> on Si(111) surface. As a result, it was found that the depth of the wear marks generated on Silicon surfaces increased in the following order: <112>, <100>, <100>. Cross-sectional TEM observations of the microwear marks were carried out. As a result, it was found that the small dislocation loops were generated in the surface region at the first stage of the microwear, and the size and the number of dislocations increased with the progress of the microwear.