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.