To easily manufacture a frame structure of a motorcycle at low cost by welding a solid joint to a main frame by single welding.

This frame structure 1 includes the pair of right and left main frames 2 inclined downward in a rear direction from a front end of a vehicle body frame 1 and constituted of an outer plate 15 constituting an outside part and an inner plate 16 constituting an inside part, and a bridge pipe 5 mounted between the main frames 2. In the frame structure 1, the solid joint 36 is connected to a lower end part of each of the main frames 2, and the bridge pipe 5 is connected to the solid joint 36.