When not in use and axis of a grommet is straight, a grommet entire length is 120% or greater and 150% or less of a distance from a through hole of a body panel to an opposing member, an accordion sleeve outer diameter is 37% or greater and 42% or less of the grommet entire length, an accordion sleeve length is 50% or greater and 55% or less of the grommet entire length, an accordion sleeve pitch is 12% or greater and 17% or less of the accordion sleeve length. When in use and the grommet is bent, an angle between opening directions of first and second openings is ninety degrees or greater, and a grommet length in the opening direction of the second opening is 82% or greater and 87% or less of the distance from the through hole of the body panel to the opposing member.