To provide a heat pump circuit for air conditioning with a simplified structure miniaturizable, facilitating piping work or the like, reducing costs, and facilitating control.

The heat pump circuit is provided with at least a heat source side heat exchanger 1, a plurality of air supply side heat exchangers 2, a compressor 3, an expansion valve 4, a low pressure liquid pipe A, a high pressure liquid pipe B, a low pressure gas pipe C, and a high pressure gas pipe D. The compressor 3 is connected to the high pressure gas pipe D and the low pressure gas pipe C, one of a refrigerant outlet or inlet of the heat source side heat exchanger 1 is connected to the high pressure gas pipe D and the low pressure gas pipe C such that a change-over can be freely carried out, another of the refrigerant outlet or inlet of the heat source side heat exchanger 1 is connected to the high pressure liquid pipe B and the low pressure liquid pipe A such that a change-over can be freely carried out, one of a refrigerant outlet or inlet of each air supply side heat exchanger 2 is connected to the high pressure gas pipe D and the low pressure gas pipe C such that a change-over can be freely carried out, another of the refrigerant outlet or inlet of each air supply side heat exchanger 2 is connected to the high pressure liquid pipe B and the low pressure liquid pipe A such that a change-over can be freely carried out, and the high pressure liquid pipe B and the low pressure liquid pipe A are connected via the expansion valve 4.

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