A vehicle body frame for a motorcycle comprising: a head pipe; a pair of left and right tank rail portions (41, 41) extending downward in a rear direction from the head pipe, each tank rail portion including successively from the head pipe a widening portion, a parallel portion, and a narrowing portion, wherein, on a frame plan view, the widening portions (45, 45) having a width between them in a frame lateral direction increasing rearwardly, the parallel portions (46, 46) having a substantially fixed width between them in the frame lateral direction and the narrowing portions (47, 47) having a width between them in the frame lateral direction decreasing rearwardly; and a pair of left and right rear arm bracket portions (42, 42) bending and extending from rear ends of the tank rail portions (41, 41), respectively, a pair of left and right engine suspension stay portions (43, 43) provided substantially downward from the tank rail portions (41, 41), the vehicle body frame is constituted by a front frame part and a rear frame part separated from each other and connected through frame connecting surfaces (61, 61) substantially perpendicular to axial directions of the parallel portions (46, 46), each engine suspension stay portion is provided with a front engine suspension portion for supporting a front portion of a motorcycle engine, characterized in that each engine suspension stay portion includes a front stay part and a rear stay part separated from each other and connected through a stay connecting surface, and each front engine suspension portion is disposed to the respective front stay part, and each front stay part and each rear stay part is integrally formed with the front frame part (10a and the rear frame part, respectively. a head pipe; a pair of left and right tank rail portions (41, 41) extending downward in a rear direction from the head pipe, each tank rail portion including successively from the head pipe a widening portion, a parallel portion, and a narrowing portion, wherein, on a frame plan view, the widening portions (45, 45) having a width between them in a frame lateral direction increasing rearwardly, the parallel portions (46, 46) having a substantially fixed width between them in the frame lateral direction and the narrowing portions (47, 47) having a width between them in the frame lateral direction decreasing rearwardly; and a pair of left and right rear arm bracket portions (42, 42) bending and extending from rear ends of the tank rail portions (41, 41), respectively, a pair of left and right engine suspension stay portions (43, 43) provided substantially downward from the tank rail portions (41, 41), the vehicle body frame is constituted by a front frame part and a rear frame part separated from each other and connected through frame connecting surfaces (61, 61) substantially perpendicular to axial directions of the parallel portions (46, 46), each engine suspension stay portion is provided with a front engine suspension portion for supporting a front portion of a motorcycle engine, characterized in that each engine suspension stay portion includes a front stay part and a rear stay part separated from each other and connected through a stay connecting surface, and each front engine suspension portion is disposed to the respective front stay part, and each front stay part and each rear stay part is integrally formed with the front frame part (10a and the rear frame part, respectively.