AIR CLEANER

There is provided an air cleaner configured to be disposed behind an engine and inside a vehicle body frame. The air cleaner includes: an air cleaner case in which an intake chamber is formed; an air filter that divides the intake chamber into a dirty side and a clean side; an inlet tube configured to take in air from a vehicle rear side to the dirty side; and an outlet tube configured to send air from the clean side to the engine. The inlet tube and the outlet tube are attached to an upper side of the air cleaner case, and an expansion portion is formed on a lower side of the air cleaner case, the expansion portion being formed by expanding the clean side further downward than the dirty side.