A grommet applied to a wire harness includes: a body (10) fitted into a through hole and stops water from entering the through hole; and an umbrella-shaped unit including an annular wall section, a first lip section, and a second lip section, the first lip section and the second lip section abutting an abutting target surface in a state in which the body is fitted into the through hole. The first lip section and the second lip section are provided in the annular wall section so as to be located within an installation region of an insulator when viewed along an axial direction. The umbrella-shaped unit includes a stress concentration section that is provided in an annular shape in the annular wall section on a center axis side with respect to the first lip section, and is located within the installation region when viewed along the axial direction.