An all terrain vehicle is constructed to prevent rainwater or the like
from entering an inner portion of an air cleaner without complicating the
structure of the vehicle or making the assembly work difficult, while
improving the external appearance of the vehicle. An air cleaner is
provided below a seat, and the air cleaner is positioned between left and
right rail main bodies when viewed from above. Left, right, bottom and
rear surfaces of the air cleaner are covered with an undercover, which is
separate from the air cleaner.