A vehicle body includes a pair of left and right main frames extending rearwardly from a front portion of the vehicle body and a seat extending rearwardly from a substantially central portion for providing seating for an occupant. A trunk is provided on the rear side of the seat for storing luggage with a backrest mounted to a front wall of the trunk for supporting the back of the occupant. The occupant includes a rider and a passenger, and the seat includes a front seating portion for the rider and a rear seating portion for the passenger arranged in tandem in the longitudinal direction of the vehicle body. A pair of left and right rear frames for supporting the trunk extend to a position below the rear seating portion, so that the load of the passenger sitting on the rear seating portion is borne by the rear frames.