To provide an engine exhaust pressure reducing device of a gas heat pump that keeps output in high load while effectively utilizing energy of exhaust heat of an exhaust gas in heating the air.

An exhaust path 40 releases the exhaust gas discharged from an engine 10 for driving a compressor to the atmospheric air. The exhaust path 40 is provided with an exhaust heat exchanger 25 for heating a cooling liquid for heating the refrigerant by the exhaust gas in the heating operation, and an exhaust pipe 41 for discharging the exhaust gas passing through the exhaust heat exchanger 25, to an upstream side of an outdoor unit fan 29.