To prevent a supporting body from being heated abnormally and damaged by feeding hot exhaust gas into a water lock.

This exhaust device is provided with a water lock 18 supported by a supporting body consisting of a plastic foaming body in the downstream of the exhaust pipe of an engine, and is constituted so that the exhaust gas of the engine may be exhausted outboard through the water lock 18. A thermal insulation layer 35 is formed at the outer periphery part of the water lock 18, and through the thermal insulation layer 35, the water lock 18 is supported on the supporting body 31. The core material 32 of the supporting body 31 is formed out of a plastic foaming body, and the water lock 18 is formed of a cylindrical tank. The supporting body 31 is formed so that its supporting surface 34 may come into surface contact with the outer periphery surface of the water lock 18 to supply cooling water in the water jacket of the exhaust pipe may into the water lock 18 together with the exhaust gas.