To provide a sealing device capable of suitably maintaining sealing action even when a main lip is worn, and capable of preventing change of rotation torque of a bearing device.

The sealing device is mounted in an annular space formed between an inner member 20 and an outer member 21 relatively rotating with each other. The sealing device is provided with a slinger 2 having a cylindrical part 2a pressed in one member 20 of the inner member 20 and the outer member 21 and an annular plate part 2b, and a seal body 3 pressed in the other member 21 of the inner member 20 and the outer member 21 and having a main lip 7 slidably and closely contacting with the cylindrical part 2a. At least one of a spare lip 10 is provided on an outer side B of the main lip 7, which is not brought into contact with the cylindrical part 2a ordinarily, and is brought into contact with the cylindrical part 2a by abrasion of the main lip 7 by rotation.