This engine (E) of a two-wheeled automobile has an engine rotary shaft (26) extending in the direction of vehicle width. Traveling wind (A) taken in anteriorly to a handlebar (6) anterior to the engine (E) is led to the engine (E) through an air intake duct (70). The air intake duct (70) extends from the anterior of the handlebar (6) to the posterior of a cylinder block (30) passing along one side of the cylinder block (30) and above a radiator (13).
