A sealing device seals a gap between a housing and a rotational shaft located in a shaft hole provided in the housing. The sealing device includes: a mounted part that is to be mounted on the shaft hole; an inner annular part; a seal lip that is to be in contact with the outer peripheral surface of the rotational shaft; a bellows part connecting the mounted part with the inner annular part; a sound insulation ring fixed to the mounted part; and a circular annular sound insulation lip projecting from the inner annular part or the bellows part toward the sound insulation ring. The sound insulation lip protrudes obliquely radially outward. The sound insulation ring includes a circular annular part with which the distal end of the sound insulation lip is in contact. The circular annular part of the sound insulation ring is inclined with respect to an axial direction of the shaft hole such that the distance between an outer portion of the circular annular part and the inner annular part when projected in the axial direction of the shaft hole is greater than the distance between an inner portion of the circular annular part and the inner annular part when projected in the axial direction.