To provide a roof spoiler structure which can be mounted on the roof of a vehicle independently of the size of luggage for reinforcing a vehicle body against external force applied to the side of the vehicle.

The roof of the vehicle has an opening portion 3 which can be opened/closed with the folding of a canvas. Spoiler rails 4a, 4b and canvas rails 4c, 4d are provided on the upper and lower sides of right and left roof side portions 2a, 2b along the longitudinal direction of the vehicle, and front pocket portions 5 are mounted on the front sides of the right and left roof side portions. Roof spoiler portions 6 are mounted on the right and left roof side portions 2a, 2b in opposition to the front pocket portions 5 so as to be slidable via the spoiler rails 4a, 4b.