A seal ring that is attached to an annular groove provided on an outer periphery of a shaft and seals an annular gap between the shaft and a housing that rotate relative to each other, to maintain fluid pressure in a sealed region in which the fluid pressure is configured to change, the seal ring is configured for sliding on a lateral wall surface of the annular groove on a lower pressure side, the seal ring comprising, on a side of a sliding surface thereof that slides on the lateral wall surface: a first groove provided at a position that falls within a sliding region in which the seal ring slides on the lateral wall surface, and extending in a circumferential direction thereof, and a second groove extending from an inner peripheral surface to a position at which the second groove enters a central position of the first groove in the circumferential direction, guiding sealed fluid into the first groove, and capable of discharging foreign matter to a side of the inner peripheral surface, the first groove having a pair of dynamic pressure generation grooves configured to have a groove bottom made shallower at an end thereof in the circumferential direction than at a center thereof in the circumferential direction on both sides in the circumferential direction across a portion where the second groove enters, and the second groove being configured to have a groove bottom deeper than the groove bottoms of the dynamic pressure generation grooves, the seal ring being characterized in that a barrier part (123X, 123Xa, 123Xb) that prevents flow of the sealed fluid from flowing from one of the dynamic pressure generation grooves to the other of the dynamic pressure generation grooves is provided between the pair of dynamic pressure generation grooves and on an outside in a radial direction of the second groove. the seal ring is configured for sliding on a lateral wall surface of the annular groove on a lower pressure side, the seal ring comprising, on a side of a sliding surface thereof that slides on the lateral wall surface: a first groove provided at a position that falls within a sliding region in which the seal ring slides on the lateral wall surface, and extending in a circumferential direction thereof, and a second groove extending from an inner peripheral surface to a position at which the second groove enters a central position of the first groove in the circumferential direction, guiding sealed fluid into the first groove, and capable of discharging foreign matter to a side of the inner peripheral surface, the first groove having a pair of dynamic pressure generation grooves configured to have a groove bottom made shallower at an end thereof in the circumferential direction than at a center thereof in the circumferential direction on both sides in the circumferential direction across a portion where the second groove enters, and the second groove being configured to have a groove bottom deeper than the groove bottoms of the dynamic pressure generation grooves, the seal ring being characterized in that a barrier part (123X, 123Xa, 123Xb) that prevents flow of the sealed fluid from flowing from one of the dynamic pressure generation grooves to the other of the dynamic pressure generation grooves is provided between the pair of dynamic pressure generation grooves and on an outside in a radial direction of the second groove. a first groove provided at a position that falls within a sliding region in which the seal ring slides on the lateral wall surface, and extending in a circumferential direction thereof, and a second groove extending from an inner peripheral surface to a position at which the second groove enters a central position of the first groove in the circumferential direction, guiding sealed fluid into the first groove, and capable of discharging foreign matter to a side of the inner peripheral surface, the first groove having a pair of dynamic pressure generation grooves configured to have a groove bottom made shallower at an end thereof in the circumferential direction than at a center thereof in the circumferential direction on both sides in the circumferential direction across a portion where the second groove enters, and the second groove being configured to have a groove bottom deeper than the groove bottoms of the dynamic pressure generation grooves,