To provide rear body part structure of a vehicle capable of suppressing increase of weight of a vehicle body and increase of the number of constituent parts and ensuring sufficient rigidity of a rear part of the vehicle body.

A rear skirt 20 having a hollow and closed cross sectional shape is formed by a rear skirt inner 21 and a rear skirt outer 25. A reinforce skirt 35 is provided on the rear skirt inner 21 and the rear skirt outer 25. A rear quarter panel inner 10 is connected with a side end fringe of the rear skirt inner 21 and the reinforce skirt 35. The rear quarter panel inner 10 and the rear skirt outer 25 are mutually connected by a rear quarter panel end 60. A rear end fringe 65a of a rear quarter panel outer 65 is connected with the rear quarter panel end 60, and the rear skirt 20 and the rear quarter panel inner 10 are mutually connected by a reinforce skirt outer 30.