To provide a piston ring provided with hard coating on an outer circumferential surface of piston ring base material, and chemical treatment coating on at least either of an upper and a lower side surfaces, in which a piston of an aluminum alloy is not abraded, and in which abrasion resistance is excellent.

The piston ring base material includes: 0.50-0.70% C, 1.65-2.50% Si, 0.50-1.50% Mn, 0.50-3.00% Cr, 0.05-0.50% V, with the rest comprising Fe and unavoidable impurities. The hard coating is formed by PVD treatment or high speed flame spraying.