Polishing slurry has abrading particles dispersed in a liquid dispersant. The abrading particles are composite particles each having a first particle and a plurality of second particles smaller than the first particles attached to the surface of the first particle through a metal oxide membrane. The first particles have average diameter of 0.1–20 μm and the second particles have average diameter of 0.001–0.5 μm. Elastic particles may be used as the first particles such as polymer particles.