To sufficiently achieve a noise reduction effect at a joining portion of a hot gas bypass pipe and a main refrigerant circuit.

An air conditioning device 1 comprises a compressor 21, a cooler, an evaporator, a bypass pipe 27 and an internal heat exchanger 24. The bypass pipe 27 has a first pipe 27a for branching a part of a refrigerant after cooled by the cooler and before flowing into the evaporator, a second pipe 27b for branching a part of the refrigerant after compressed by the compressor 21 and before flowing into the cooler, and a third pipe 27c for joining the refrigerant flowing in the first pipe 27a and the refrigerant flowing in the second pipe 27b, and joining it to the refrigerant after evaporated by the evaporator and before turned to the compressor 21. The internal heat exchanger 24 exchanges heat between the refrigerant after joined with the refrigerant flowing in the bypass pipe 27 and before returned to the compressor 21 and the refrigerant after cooled by the cooler and before flowing into the evaporator.