To provide a mounting device whereby a mounting part can be easily mounted in a lock stud, but the mounting part is difficult to be removed.

In a mounting device having a lock stud and a mounting part, capable of easily mounting the mounting part in the lock stud, to be provided with a mounting part 10 having a receiving space 11 for receiving a lock stud 1, when the mounting part 10 is mounted, an inner surface 18 of the receiving space 11 and a peripheral surface of the lock stud 1 are mutually friction connected, the peripheral surface has a structure having a crest-shaped relief 7 extended substantially in a peripheral direction of at least one of dimensionally stable material, and the inner surface 18 has a relief 13 of at least one of plastically deformable material extended substantially in a cross direction relating to the peripheral direction. In any of the cases, radial direction elasticity of the lock stud 1 given by a slot is increased by an additional axial direction hole 9.