To provide a refrigeration cycle of air conditioning equipment which can improve performance during the cooling operation without lowering heating performance.

In a refrigeration cycle of air conditioning equipment which comprises a compressor 2, a four-way valve 3, an outdoor heat exchanger 4 having two passes 4a and 4b, a throttle 5 and an auxiliary heat exchanger 6 housed in an outdoor unit 1, and a room heat exchanger 11 having two passes 11a and 11b housed in a room unit 10 and builds a refrigerant circuit by piping these components sequentially, the auxiliary heat exchanger 6 for sub cool is arranged between the outdoor heat exchanger 4 and the throttle 5, and a bypass circuit is provided across both ends of the auxiliary heat exchanger 6 to be equipped with a check valve 7 for bypassing so that the refrigerant will not flow through the auxiliary heat exchanger 6 during the heating operation.