Abstract: A front crossbar of a roof rack provided above a roof along the width of a vehicle comprises an upper surface and a lower surface. The upper surface is smoothly curved and convex toward the upper direction, and the upper surface introduces an attached flow of air from the front of the vehicle to the rear of the vehicle. The lower surface of the front crossbar comprises a flow compression face in the front of the lower surface, a flow leading face in the center of the lower surface, and a flow separation portion in the rear of the lower surface. The flow compression face is hollowed toward the center point of the cross-section of the front crossbar, and introduces and compresses the air flow from the front of the vehicle. The flow leading face is a smooth convex arc of a circle as the cross-section, and leads the air flow compressed from the front of the front crossbar to the rear of the front crossbar.