To provide excellent workability for mounting a spoiler on a bumper and simplify the structure of a molding die for the spoiler.

In the mounting structure for a spoiler 3 mounted on the bumper of a vehicle in such a way as to cover the lower end of the bumper is provided with a mounting hole for mounting the spoiler, and a mounting part 4 mockingly inserted into the mounting hole is provided integrally with the spoiler. The mounting part 4 comprises a base piece 41 and a front piece provided via a curved part 42. With the mounting part 4 lockingly inserted in the mounting hole, the front piece is folded on the back of the base piece 41 via the curved part 42 and is lockingly inserted into the mounting hole. The base piece 41 has a first elastic pawl 411, and the front piece has a second elastic pawl 431.