Abstract: A grommet 1 includes a corniced part 2 in a shape of a bellows, and two engaging parts 3, 4 integrally formed on opposite ends of the corniced part and adapted to be engaged with respective bodies to be fitted such as a chassis panel 5 and a door panel 6. The grommet 1 is formed in a hollow tubular shape in such a manner that the corniced part 2 is smaller in diameter than the engaging parts 3, 4. The grommet 1 can be obtained by molding thermoplastic elastomer by injection molding so that the diameter of the engaging parts is less than five times as large as the diameter of the corniced part, opening molds 17, 18 for forming an outer face thereof, and thereafter, enlarging the corniced part thereby removing the grommet from a core 19 for forming an inner face thereof.