Abstract: A slurry containing abrasive grains and a liquid medium, in which the abrasive grains include first particles and second particles in contact with the first particles, a particle size of the second particles is smaller than a particle size of the first particles, the first particles contain cerium oxide, the second particles contain a cerium compound, and in a case where a content of the abrasive grains is 0.1% by mass, a BET specific surface area of a solid phase obtained when the slurry is subjected to centrifugal separation for 60 minutes at a centrifugal acceleration of 1.1×104 G is 40 m2/g or more.