An air valve comprises a casing, a valve body driving assembly and a valve body. The casing comprises a chamber, a vent hole, and at least one switching hole communicating with the chamber. The valve body driving assembly is disposed in the chamber, and comprises a pusher, a shape memory metal wire in a linkage relationship with the pusher, and two conductive members disposed in the casing and located at two ends of the shape memory metal wire respectively, the pusher travels a uniaxial displacement stroke due to a temporary change of the shape memory metal wire. The valve body is disposed in the chamber and faces the switching hole, when the pusher travels the uniaxial displacement stroke, the valve body is driven to rotate a central angle relative to the switching hole to change a ventilation state between the switching hole and the chamber.