An air intake system for a saddle-ride vehicle for facilitating the intake of fresh air and for enabling a discharge of excess pressure in an air cleaner box. The system includes an air cleaner box with an air cleaner element housed in an air cleaner case and an intake duct connected to the air cleaner box with an intake port open toward a vehicle front side, in which the intake duct has a duct opening oriented outward of the duct between the intake port and the air cleaner box. The air cleaner box includes parts for connecting the intake duct, a connecting tube and also case openings oriented outward of the case.