To provide a back plate mounting flange of a vehicle which can accurately apply a sealant to a mating face for mounting a back plate with excellent productivity.

The back plate mounting flange 2 of the vehicle is a member mounted on both right and left ends of an axle arranged along the vehicle width direction. The back plate mounting flange 2 of the vehicle is mounted with the back plate of a drum brak, and the sealant 4 is applied to the mating face for mounting the back plate. A recessed part 12 for indicting a position of a through-hole formed in the back plate is formed on the mating face for mounting the back plate of the back plate mounting flange 2. The recessed part 12 is also formed simultaneously with forging, and the depth of the recessed part 12 is formed in the size of not removing the recessed part 12 by cutting work of the mating face for mounting the back plate.