To provide an air valve capable of preventing the leakage in closing a valve element by preventing the inclination of the valve element.

A lid body 4 mounted on an upper part of a valve casing 2 is provided with an exhaust hole 7 for exhausting the air in the valve casing 2 to the external, a floating valve 8 vertically movable to open and close the exhaust hole 7, and an opening direction energizing means 10 for energizing the floating valve 8 in the opening direction O. A float for energizing the floating valve 8 to the closing direction is mounted in the valve casing 2, the float is constituted to press up the floating valve 8 in the closing direction by a float rod 11b by the rise of a float main body, and the float rod 11b is held in a state of being vertically movable within a specific range by a float holding means 35 mounted at a valve casing 2 side in a state of being separated and independent from the floating valve 8, and separated from the floating valve 8 at its upper end to be kept into contact with and separated from the floating valve 8.