To provide an air valve and a hydrant with the air valve in which the production costs can be reduced, and the work can be simply carried out, at low costs.

The air valve 1 is provided with a cylindrical casing 4 in the erected posture in which a ventilation hole 3 is opened at an upper end 2, a pillar-shaped float needle valve 5 which is long in the vertical direction and movably inserted up and down in the cylindrical casing 4, and a valve seat 6 which is installed around the ventilation hole 3 in the cylindrical casing 4 and makes the pillar-shaped float needle valve 5 rising with the buoyancy from water supply in close contact. The hydrant 8 with the air valve is equipped with the air valve 1 at the side of the valve housing 13.