An air conditioning device includes a main refrigerant circuit and a discharge-intake bypass circuit. The refrigerant circuit is operable in a heating mode and a positive cycle defrosting mode. It is possible for refrigerant to bypass from a discharge side to an intake side of the compressor when the refrigerant circuit is operating in the heating mode. The refrigerant circuit is operable in a positive cycle defrosting mode. When the refrigerant circuit is operating in the positive cycle defrosting mode, a superheat valve of the discharge-intake bypass circuit is opened and the refrigerant is caused to bypass from the discharge side to the intake side of the compressor through the bypass circuit and a defrosting-mode main valve high-pressure control is performed to adjust a valve opening of a main valve so that a high pressure level of a refrigerating cycle in the refrigerant circuit reaches a target high pressure.