To provide a vehicle body frame for a motorcycle capable of reducing structure members, and improving welding workability and a yield of material.

In the motorcycle vehicle body frame composed of one pipe-shaped main frame portion 2, a pivot supporting frame portion 3, and a pair of right and left seat rail portions 4, left side half portions of a main frame portion 2 and the pivot supporting frame portion 3 are structured by a semi-cylindrical left frame half element 27L made from a series of plate materials, and right side half portions are structured by a semi-cylindrical right frame half element 27R made from the series of plate material. Opposite end portions of both frame half elements 27L, 27R are united with each other. An upper space between the right and left half portions of the pivot supporting frame portion 2 is coupled through a coupling plate 28, and a front end of an outside half portion 4A of a seal rail portion 4 is welded to the frame half elements 27L, 27R. A front end of an inside half portion 4B is welded to the coupling plate 28 at a position deviating from the front end of the outside half portion 4A.