PURPOSE: To make a titanium-nitride layer thick enough as well as to form it into nonseparableness by forming steel and titanium into a coil form by means of clad rolling, and then molding a coil material into a piston ring form so as to cause an outer circumferential surface of the piston ring to become the titanium layer, in the piston ring consisting of steel.

CONSTITUTION: A piston ring body 1 consisting of steel and a titanium or titanium alloy layer 2 are subjected to clad rolling whereby the piston ring body 1 and the titanium layer 2 are joined together, molding them into a coil form. Next, this coil material is molded into a piston ring form by means of drawing, and it is thus manufactured so as to cause its outer circumferential surface, serving as a contact surface with a cylinder bore, to become the titanium alloy layer. In addition, this piston ring is applied to nitriding by means of gas soft nitriding to be treated in an ammonia cracked gas, and a titanium nitride layer 3 is formed at the side of an outer circumferential surface serving as a sliding surface with the cylinder bore of the titanium layer 2. By this constitution, the titanium nitride layer can be made thick enough and, what is more, no separation occurs.