To reduce a consumption amount of abrasive and reduce scratch generating in an object to be polished due to the expansion of a grain diameter of abrasive in a polishing device employing a chemical and mechanical polishing method.

A polishing head 2 has a slurry supply pipe 4 supplying slurry S, a diaphragm member 8 as a hold means holding a wafer W in a recessed part 5 for holding formed in the polishing head 2, a retainer ring 9 forming a closed space K2 in which slurry S remains between the wafer W and a polishing pad 11 due to the close contact with the polishing pad 11, and a valve mechanism 41 opening and closing a supply port supplying slurry S into the closed space K2 from the slurry supply pipe 4.