To provide a grommet which inhibits breakage by friction with a harness in a simple structure.

The grommet 10, which is provided on the connection part of a vehicle body 2 and a side door 3 movable to the vehicle body 2 and through which the harness 5 is passed, includes: a grommet body 11, on which a vehicle body side engaging cylindrical part 13 engaged with the vehicle body 2, a door side engaging cylindrical part 14, which engages with the side door 3, and a bendable bellows portion 15, which connects between the vehicle body side engaging cylindrical part 13 and the door side engaging cylindrical part 14, are formed; and a harness restraining portion 12, which projects from its inner circumferential surface farther inward from its minimum inner diameter of bellows portion 15 on the inner circumferential surface of the grommet body 11 to inhibit the harness 5 from contacting the inner circumferential surface of the bellows portion 15.