The fatigue ratio [fatigue limit (σW) / tensile strength (σB)] of bulk metallic glass (BMG) was initially smaller by an order of magnitude than that of the crystalline structural alloys of 0.3 to 0.6. Then, the BMG was regarded as useless for structural members. However, the σW/σB of BMGs increased with increasing the year, and recently a large value of about 0.8 was shown for a Ti-based BMG, and the maximum cyclic stress (σmax) was about 90% of the σB. Since BMG has no dislocation, it may not show fatigue. Therefore, in this report, using high-purity elements, the Zr-based BMG with less impurities and less defects was made by arc-melt Cu mold tilt casting method, which is expected to have less impurities or defects, and fatigue strength of the BMG was examined by also paying attention to the polishing of the specimen surface. As a result, higher value of the σW/σB about 0.8 ~ 0.9, and the σmax/σB of about 0.9 ~ 1.0 were shown. In addition, the influence of increase in number of casting times with same master BMG, which raises the yield rate of the master BMG, on the σB and σW and the influence of the specimen surface polishing level on the σW are reported.
