Consequently, the retainability of the slurry at the time of polishing is high, the retainability of the slurry is easily recovered by surface renewal, and further the scratching on the surface of the material to be polished can be prevented. [0052] Examples of the above crosslinked polymer include polymers obtained by crosslinking resins such as polyurethane resin, epoxy resin, polyacrylic resin,