A polishing composition contains a deterioration inhibitor for inhibiting deterioration of polishing capability of the polishing composition, an abrasive, and water. The deterioration inhibitor is at least one selected from polysaccharide and polyvinyl alcohol. The polysaccharide is starch, amylopectin, glycogen, cellulose, pectin, hemicellulose, pullulan, or elsinan. Among them, pullulan is preferable. The abrasive is at least one selected from aluminum oxide and silicon dioxide, preferably at least one selected from fumed silica, fumed alumina, and colloidal silica. The polishing composition can be suitably used in polishing for forming wiring a semiconductor device.