ENGINE

A combuster (2) of a gas turbine engine (1) is fed with gaseous ammonia and that gaseous ammonia is burned to drive a turbine (3). Inside the exhaust passage of the gas turbine engine (1), an NO x selective reduction catalyst (10) is arranged. Inside one or both of the intake passage of the gas turbine engine (1) or the exhaust passage upstream of the NO x selective reduction catalyst (10), ammonia is fed. This ammonia is used to reduce the NO x which is contained in the exhaust gas at the NO x selective reduction catalyst (10).