Provided is a sealing device with which an increase in sliding resistance can be prevented and sliding resistance can be stabilized even when a lead seam is formed in a lip contact portion. This sealing device (1) is equipped with an annular reinforcing ring (10) around an axial line (x), and an annular elastic body part (20) around the axial line (x) formed from an elastic body attached to the reinforcing ring (10). The elastic body part (20) has a side lip (21), an intermediate lip (22), and a grease lip (23). A grease (G) is applied as a lubricant to the respective inner circumferential surfaces (21a), (22a), and (23a) of the side lip (21), the intermediate lip (22), and the grease lip (23). The grease (G) does not include a urea-based thickener as a thickener. When the sealing device (1) is in use the cross-sectional area (A) of a lip-to-lip space (S) surrounded by the side lip (21), the intermediate lip (22), and a hub ring (55) is no less than 3.5 mm2.