An exhaust apparatus for a process apparatus which processes an object using a process gas includes an exhaust pipe to be connected to an exhaust port of the process apparatus, and a trap mechanism connected to the exhaust pipe, for removing an impurity gas contained in an exhaust gas from the process apparatus. A reaction-gas supply mechanism is provided in the exhaust pipe at an upstream of the trap mechanism, for feeding a reaction gas which is reacted with the impurity gas in to exhaust pipe to lower a vapor pressure of the impurity gas.