To provide a rear floor luggage box and a method of manufacturing the same, configured to reduce installation manhours, weight, and the number of part items.

This rear floor luggage box 10 includes a rear floor pan 11 for constituting a rear cargo room of an automobile and formed of a resin base material, and a back door scuff 14 integrally formed in the rear floor pan 11 and forming an opening part of the rear cargo room. A pair of rear bumper attachment brackets 15 are integrally formed on an outer surface of a peripheral wall 12 of the rear floor pan 11. The resin base material is formed of a laminated sheet composed of a polypropylene resin sheet and a glass fiber mat. This rear floor luggage box 10 is provided by integrally molding the back door scuff 14 in the rear floor pan 11 by compressing the laminated sheet by a press molding method.