To provide a polishing composition capable of reducing a surface roughness of a silicon wafer and accelerating a polishing speed.

The polishing composition is used for polishing the silicon wafer and contains silicon dioxide, alkali compound and anion surfactant. The anion surfactant is at least one kind chosen out of sulfonic acid system surfactant, carboxylic acid system surfactant and sulfate system surfactant. It is desirable that the silicon dioxide consists of colloidal silica or fumed silica, and the colloidal silica is more desirable. It is desirable that a content of the anion surfactant is 0.00008 to 1.6 mass %.