To improve the efficiency of ice making capacity in a heat regenerative air conditioner having a heat storage tank and an ice making heat exchanger submerged in the heat storage tank to enable an ice making operation.

The heat regenerative air conditioner 20 has: an outdoor unit 21 comprising a compressor 1, an outdoor heat exchanger 3, the heat storage tank 6, and the ice making heat exchanger 5 submerged in the heat storage tank 6 and constituted of a heat exchanger tube 5a in which a refrigerant flows; and indoor units 14 comprising an indoor heat exchanger 13, and connects the units with inter-unit piping 22 to enable an ice making operation and an ice-used cooling operation. The heat exchanger tube 5a is provided with heat exchange promoting means 5b.