To shield the sound at a cavity portion of a grommet hole portion, by providing the structure that a sound shielding plate is fixed in the side of a large aperture and a sound shielding layer is exposed in the external side of the grommet body.

A sound-shielding body 41 is loaded in such a manner that a sound shielding plate is fixed at the engaging portion at the internal side of a large aperture 33 and a sound shielding layer 47 is exposed at the external side of a grommet body 37. Thereby, the sound shielding layer 47 does not change even when the grommet body 37 is fitted to a body panel 23. As a result, unexpected force causing disengagement of the sound shielding plate 41 due to deformation of the sound shielding layer 47 is never generated and therefore a gap causing leak of sound is never formed at the cavity generated by cutting out the sound shielding member 27 to fit the sound proof grommet 21, thereby the sound can be shielded.