A grommet includes a fitting body causing a fitting groove to be fitted to a circumferential edge of a through hole, and a first tubular body and a second tubular body. The fitting body includes a tubular portion, a rib rising from an outer circumferential wall surface of the tubular portion, and a locked portion disposed radially inside the rib, rising from the outer circumferential wall surface, and configured to be locked to an outer circumferential surface of the first tubular body, to suppress elastic deformation of the tubular portion or reduce elastic deformation amount. The rib is elastically deformable in a circumferential direction, and the outer circumferential wall surface has a plurality of projection groups constituted by the locked portion and a plurality of ribs disposed radially outside the locked portion.