A vehicle body frame of a motorcycle comprises a front frame portion extending rearward from a head pipe, and a rear frame portion extending downward or rearward from a rear end of the front frame portion. The front frame portion includes at least a pair of right and left frame members. A front end of the rear frame portion is welded to a center cross member coupling rear ends of the frame members. The center cross member has a closed cross-section structure in which plate members are joined together in a forward and rearward direction. Thus, a fuel tank and devices can be laid out more flexibly from a location above the center cross member to a location behind the center cross member more flexibly and mounted more easily.