To provide an air release valve having large vacuum break ability and capable of quickly performing vacuum break.

A valve chest 3 with an inflow port 4 and an outflow port 5 opened in a lower part and an upper part, respectively, is formed by a casing constituted of a main body 1 and a cover 2. A valve seat 6 is formed between the valve chest 3 and the inflow port 5. The main body 1 integrally has a plurality of ribs 9 projecting to the inside at an inner wall of the valve chest 3. At the inside of the ribs 9, a float receiver 10 having a bottomed and almost cylindrically shaped through hole 11 of small opening area at a bottom part and a communication hole 13 of large opening area is fixed. Within the float receiver 10, a spherical float 12 is arranged in a free state. A check valve body 14 for opening/closing the communication hole 13, allowing flow from the inside to the outside of the float receiver 10 and stopping flow of an opposite direction is fixed at the outside of the float receiver 10. Because external air flowing into the float receiver 10 can be passed to the outside of the float receiver 10 by the communication hole 13 of large opening area, air seldom springs back by hitting on the bottom part of the float receiver 10 and pressure in the lower part of the float 12 within the float receiver 10 becomes difficult to rise. Therefore, the float 12 becomes difficult to float, vacuum break ability becomes large and vacuum break can be quickly performed.