The invention provides a roof side rail for a vehicle, thereby suppressing increase of weight of the vehicle and effectively improving torsional rigidity of the vehicle body. The present invention relates to roof side rails (3 and 10) for a vehicle, including a roof inner side panel (6) and a roof outer side panel (7) which are arranged along a longitudinal direction of the vehicle to oppose each other while forming a closed section (S), wherein a V-shaped wedge (cl) formed by the roof inner side panel (6) and the roof outer side panel (7) is provided in a lower region of the closed section (S). In the roof side rails (3 and 10), a reinforcing component (9) is provided in a space inside the wedge (c1), or a foam filling component (11) is provided at least in the space inside the wedge (cl) in the closed section (S), and the reinforcing component (9) or the foam filling component (11) is joined to the roof inner side panel (6) and the roof outer side panel (7).