To provide an abrasive slurry having high dispersion stability, including: abrasive fine particles made of one or more kinds of oxides; colloidal fine particles made of colloidal oxide with an average particle size smaller than an average particle size of the abrasive fine particles; and a dispersion medium in which the abrasive fine particles and the colloidal fine particles are dispersed, and a manufacturing method for a substrate as an inorganic substrate, including polishing the substrate using the abrasive slurry. An abrasive slurry according to the present invention keeps high dispersion stability for a long time and shows a satisfactory redispersion property, which can eliminate a problem about precipitation/aggregation as much as possible and can be used as a dispersant-free abrasive containing absolutely no organic dispersant. In particular, by using the abrasive slurry, it is possible to manufacture a substrate such as a silicon substrate used in a semiconductor manufacturing process or an aluminum substrate used in an electrostatic chuck manufacturing process through CMP with industrial advantage.