PURPOSE: To lengthen a seal lifetime by setting the first lip as an independent lip, bringing respective edge parts of the second lip including the edge parts of the first lip into contact with a shaft successively at a certain interval, and forming grooves between the respective lips.

CONSTITUTION: When oil seal is installed on a shaft, the edge part 3a' of the first lip 3 and plural number of edge parts 4a', 4b' and 4c' of the second lip 4 are brought into contact with each other successively at a certain interval. That is, the edge parts 3a', 4a', 4b' and 4c' of the respective lips are bent so that the respective edge parts are brought into contact with a shaft surface successively to form grooves 10a', 10b' and 10c' between the edge parts of the respective lips. The groove 10a' is a single independent groove, and by means of this groove 10a, oil as a seal object can be prevented from leaking outside of the seal when the shaft is stopped. Since interference of the edge parts 3a', 4a', 4b' and 4c' of the respective lips can be utilized until the interference is abraded completely to the extent of an abrasion example 1 or an abrasion example 2 so that the oil seal lifetime can be lengthened significantly.