A sealing device (20, 60) located between an inner member and an outer member that rotate relative to each other, for sealing a gap between the inner member and the outer member, the sealing device (20, 60) comprising: a tubular part (26, 66) having a central axis (Ax) and for being mounted on a cylindrical end portion of the outer member; an annular part (27, 67) connected to an end of the tubular part (26, 66) and having a portion located radially inside the end portion of the outer member; and at least one lip (32, 34, 36) extending from the annular part (27, 67) toward the inner member, each of the annular part (27, 67) and the tubular part (26, 66) comprising an elastic part made of an elastic material and a rigid part made of a rigid material, the annular part (27, 67) comprising an upper surface (40, 68A) that is opposite to the tubular part (26, 66) and that is formed of the elastic part, the tubular part (26, 66) comprising a lower surface (26A, 66A) that is opposite to the annular part (27, 67), multiple protrusions (42, 54, 72) being formed on the upper surface (40, 68A) of the annular part (27, 67), the protrusions (42, 54, 72) protruding along an axial direction of the sealing device (20, 60), the multiple protrusions (42, 54, 72) being arranged on a circle centered on the central axis (Ax) and spaced apart from each other, characterized in that when multiple sealing devices (20, 60) of the same type are stacked, top surfaces of the protrusions (42, 54, 72) of a lower sealing device (20, 60) are in contact with the lower surface (26A, 66A) of the tubular part (26, 66) of an upper sealing device (20, 60) and are not in contact with any portions of the tubular part (26, 66) of the upper sealing device (20, 60) other than the lower surface (26A, 66A). a tubular part (26, 66) having a central axis (Ax) and for being mounted on a cylindrical end portion of the outer member; an annular part (27, 67) connected to an end of the tubular part (26, 66) and having a portion located radially inside the end portion of the outer member; and at least one lip (32, 34, 36) extending from the annular part (27, 67) toward the inner member, each of the annular part (27, 67) and the tubular part (26, 66) comprising an elastic part made of an elastic material and a rigid part made of a rigid material, the annular part (27, 67) comprising an upper surface (40, 68A) that is opposite to the tubular part (26, 66) and that is formed of the elastic part, the tubular part (26, 66) comprising a lower surface (26A, 66A) that is opposite to the annular part (27, 67), multiple protrusions (42, 54, 72) being formed on the upper surface (40, 68A) of the annular part (27, 67), the protrusions (42, 54, 72) protruding along an axial direction of the sealing device (20, 60), the multiple protrusions (42, 54, 72) being arranged on a circle centered on the central axis (Ax) and spaced apart from each other, characterized in that when multiple sealing devices (20, 60) of the same type are stacked, top surfaces of the protrusions (42, 54, 72) of a lower sealing device (20, 60) are in contact with the lower surface (26A, 66A) of the tubular part (26, 66) of an upper sealing device (20, 60) and are not in contact with any portions of the tubular part (26, 66) of the upper sealing device (20, 60) other than the lower surface (26A, 66A).