An air conditioner includes a compressor for compressing refrigerant, an exterior heat exchanger for performing heat exchange between refrigerant and outside air, an interior heat exchanger for performing heat exchange between the refrigerant and air to be blown into the compartment, an ejector for decompressing high-pressure refrigerant, a heater core for heating air using a high-temperature fluid as a heating source, and a fluid-refrigerant heat exchanger that heats the fluid flowing to the heater core using high-temperature refrigerant discharged from the compressor as a heating source. In a dehumidifying and heating operation, refrigerant in the interior heat exchanger absorbs heat from air so that the air is cooled and dehumidified, and the dehumidified and cooled air can be further heated in the heater core by indirectly using the heating source from the high-temperature refrigerant.