To provide a mounting structure of a belt molding for providing ease of assembly.

The mounting structure of the belt molding includes a first hole 123 provided on a door side, having an opening that opens in a horizontal direction, and facing a side face on a cabin side of the belt molding 111, a lip part 117 pressed and abutted to an outer wall face of an outer panel 101 of a door at lower than a waist part W and generating upward pressing force to reaction force of press contact, a belt molding body 113 provided along the waist part W of the outer panel 101, and a first hole insertion part 135 provided at the belt molding body 113, inserted in the first hole 123, abutted on an upper part inner wall face 123a of the first hole 123, and being flexible in an approaching/separating direction to/from the upper part inner wall face 123a of the first hole 123.