Grommet having a resilient flange

A grommet (10) is provided for positively mounting a long member (e.g. a wire harness) in such a manner that the long member is passed through a mounting plate (11) such as a panel of a vehicle body. A grommet for passing and holding a wire harness relative a mounting hole (12) formed through a mounting plate (11) includes a first cylindrical portion (21) for passing the wire harness therethrough, a second cylindrical portion (22) connected to the first cylindrical portion (21) through a connection portion, a groove (24) formed in an outer peripheral surface of the second cylindrical portion, and a flange portion (25) formed on that portion of the outer peripheral surface of the second cylindrical portion (22) lying between the groove (24) and the connection portion (23). A plurality of guide portions (30), extending radially from the outer peripheral surface of the first cylindrical portion (21), are brought into contact with an inner peripheral edge of the mounting hole (12) in such a manner that the second cylindrical portion (22) is disposed coaxially with the mounting hole (12).