Abstract: Disclosed is a polishing slurry for sapphire polishing that is capable of obtaining polishing speeds and smooth surfaces during the polishing of sapphire substrates that are equivalent to or better than in prior polishing processes even if the number of polishers and polishing hours are reduced. Also disclosed is a sapphire substrate polishing method. The slurry includes alumina abrasives and has a pH adjusted to the range of 10.0 to 14.0, and the sapphire is polished by means of the CMP technique by applying said slurry. The aforementioned alumina abrasives more preferably include at least ?-alumina, and the content thereof is more preferably 0.01 to 50 wt %. The mean particle size of the aforementioned alumina abrasives is preferably 0.05 to 10 ?m.