To improve a degree of freedom of an appearance constitution and a part arrangement structure, in a seat rail of a vehicle body frame.

The vehicle body frame includes a pair of right-left main frames 10 extending backwArd or backward downward from a steering head pipe 101, and a pair of right-left seat rails 15 having the front end connected to the rear end side of the main frames 10 and extending backward or backward upward. A cross member 20 formed in a substantially U shape or a substantially V shape in a plan view is connected so that a width in the lateral direction gradually reduces backward to the rear end of the seat rails 15. Thus, the degree of freedom of the appearance constitution is improved by restraining an overhang of a vehicle body cover by reducing a size in the vehicle width direction on the rear side of the substantially U shape or the substantially V shape in a plan view. Efficient part or layout arrangement is realized by opening a storage space S via its recessed part on the front side of the substantially U shape or the substantially V shape in the plan view.