An engine driven heat pump is such that when a self-sustaining switch is turned on during power failure, and a self-sustaining signal is received, it switches to a self-sustaining mode and start an engine and a generator, and when output power from an inverter is received, it supplies the output power to a power supply circuit and a battery charging circuit by means of an independent power supply relay, and it supplies the output power to the outside via an independent output unit, and during the supply of the output power, it maintains cutoff with respect to connection between a system, and the power supply circuit and the battery charging circuit by means of a system cutoff relay and maintain the output of the output power until the self-sustaining signal is interrupted, and it recovers the connection when power is restored and the output power is interrupted.