A polishing composition according to the present invention contains abrasive grains, a basic inorganic compound, an anionic water-soluble polymer, and a dispersing medium, in which a zeta potential of the abrasive grains is negative, an aspect ratio of the abrasive grains is 1.1 or less, in a particle size distribution of the abrasive grains obtained by a laser diffraction/scattering method, a ratio D90/D50 of a particle diameter D90 when an integrated particle mass reaches 90% of a total particle mass from a fine particle side to a particle diameter D50 when the integrated particle mass reaches 50% of the total particle mass from the fine particle side is more than 1.3, and the basic inorganic compound is an alkali metal salt.