Provided is a polishing composition that allows yielding a smooth surface comparable with or more than a surface produced by an abrasive-free polishing composition, and can be preferably used under both condition of low pressure and high pressure, in polishing of a hardness material. The polishing composition is a polishing composition for polishing a material having a Vickers hardness of 1500 Hv or more. The polishing composition contains particles and an oxidant, and the content of the particles is less than 400 ppm.