To provide an exhaust valve capable of opening/closing a valve port with a large opening area over low pressures to high pressures.

An inlet 4, a valve chamber 3, and an outlet 11 are formed by a casing formed of a body 1, a bottom cover 2, and a valve seat member 9. An upper valve port 12 and a lower valve port 13 with the same opening area are formed in a valve seat member 9 on a vertically same axis for communicating a valve chamber 3 with the outlet 11. A float valve 14 opening/closing the lower valve port 13 is disposed in the valve chamber 3 on the lower side of the lower valve port 12, and a valve element 15 opening/closing the upper valve port 12 is disposed on the outlet 11 side between the upper valve port 12 and the lower valve port 13. A lower guide bar 17 is formed integrally with the lower surface of the valve element 15. When the float 14 is seated on the lower valve port 13 and the valve element 15 is seated on the upper valve port 12, the lower end face of the lower guide bar 17 is brought into contact with the upper end face of the the float.