A sealing device (1) having: a slide ring (2) and a back ring (3). The sealing device (1) is configured to seal an annular gap between a housing having a shaft hole, and a shaft inserted through the shaft hole. The slide ring (2) has: a through-cut (22), comprising a circumferential cut (22A), and axial cuts (22B) extending from both ends of the circumferential cut, along the axial direction; and multiple parting lines (23A, 23B) formed on a surface of the slide ring (2). The parting lines (23A, 23B) are arranged so that the parting lines (23A, 23B) are not overlapped with the circumferential cut (22A) exposed at the junction surface of the slide ring (2) with the back ring (3), throughout the lengthwise direction of the circumferential cut.