A polishing slurry containing a slurry dispersing particles of tetravalent metal hydroxide in a medium therein and an additive, characterized in that the additive is a polymer containing at least one kind of monomer component selected from a group of monomers represented with a general formulae (I) and (II) below (In the general formulae (I) and (II), R1 denotes hydrogen, a methyl group, a phenyl group, a benzil group, a chlorine group, a difluoromethyl group, a trifluoromethyl group or a cyano group, R2 and R3 denote hydrogen or an alkyl chain having 1 to 18 carbon atoms, a methylol group, an acetyl group or a diacetonyl group, and a case where both are hydrogen is not included. R4 denotes a morpholino group, a thiomorpholino group, a pyrrolidinyl group or a piperidino group.) The invention provides a polishing slurry in which particles form a chemical reaction layer with a polishing film to be removed with a very small mechanical action of the particles and mechanical removal by a pad without scratches and the additive realizes high planarity.