Engine of a straddle-type vehicle

Engine (E) is mounted on a motorcycle, an engine rotational shaft extending in the vehicle width direction (39), and a supercharger (62) disposed to the rear of the cylinder block (42). Engine (E) further, the running wind flowing through the traveling direction forward with respect to the engine (E) to (A), is provided with an intake duct for introducing the supercharger (62) (70). Intake duct (70) is connected through the side of the engine (E) to the inlet of the supercharger (62) (66).