To enable to retain a grommet after inserting it from one opening into a through hole of a car body panel while pulling it from the other opening, and enable to correct oblique insertion of the grommet.

This is the grommet which is equipped with a small diameter cylindrical part, a diameter-expanded cylindrical part continued to one end of the small diameter cylindrical part, and a annular car body locking recess part at the outer peripheral face of the large diameter side of the diameter-expanded cylindrical part, and in which after the small diameter cylindrical part side is inserted from one face side of the car body panel into the through hole and penetrated, the car body locking recess part is locked at the car body panel by pulling the small diameter cylindrical part penetrated from the other face side of the car body panel. With a spacing on the outer peripheral face of the diameter-expanded cylindrical part in the peripheral direction, a plurality of protruded stage parts existed extendedly in the axial line direction from the small diameter cylindrical part to the car body locking recess part are installed, at the outer faces of the respective protruded stage parts, angle ribs protruded from a coupling end are installed between the coupling end of the small diameter cylindrical part side and a position contacted with the peripheral edge of the through hole at a time of being inserted into the through hole, the grommet is temporarily retained by retaining the inclined faces of the angle ribs at the inner peripheral face of the through hole, and the peripheral edge of the through hole is made to be contacted at a position that does not exceed the car body locking recess part on the upward side in a state of temporally placing the grommet.