Provided is a piston ring for an internal combustion engine that enables size reduction of a chamfered edge without leading to the chipping, and sufficient size reduction of a flow passage of a blow-by gas in a piston ring gap, thus effectively restraining the blow-by gas from passing through the piston ring gap. A piston ring 1 with a piston ring gap 2 used for an internal combustion engine includes a chamfered edge 3 continuous to at least one of piston ring end faces at the piston ring gap 2 and an outer peripheral surface 1a of the piston ring 1. The chamfered edge 3 has a curved shape.