A frame for a vehicle to accommodate a large-sized accessory, such as a fuel tank, to be mounted downwardly of a rear pipe without having to lower a rear sub-pipe. A large-sized accessory, such as a fuel tank, can be inserted into a space under a rear pipe by removing a second rear sub-pipe from a main frame and the rear pipe. The second rear sub-pipe can be fixed to the main frame and the rear pipe by simply tightening bolts. Similarly, by simply loosening the bolts the second rear sub-pipe can be removed from the main frame and the rear pipe and the large-sized accessory can be removed onto an outside in a vehicle width direction. This facilitates mounting and helps reduce the number of man-hours involved in mounting the accessory.