An air conditioner has a refrigerating cycle in which a refrigerant flows through a compressor 6, a four-way valve 8, an indoor heat exchanger 16, an expansion valve 12, an outdoor heat exchanger 14, and the four-way valve 8 in this order during heating, and also has a heat storage tank 32 that accommodates a heat storage material 36 for storing therein heat generated by the compressor 6 and a heat storage heat exchanger 34,. The air conditioner includes a heat storage bypass circuit for connecting a refrigerant pipe between the indoor heat exchanger 16 and the expansion valve 12 and a refrigerant pipe between the four-way valve 8 and an inlet port defined in the compressor 6, a defrosting bypass circuit for connecting a refrigerant pipe between the expansion valve 12 and the outdoor heat exchanger 16 and a refrigerant pipe between an outlet port defined in the compressor 6 and the four-way valve 8, and a heat storage two-way valve 42 provided in the heat storage bypass circuit. Also, a normal heating mode and a quick heating mode are provided, and a warm wind is blown out more quickly in the quick heating mode than in the normal heating mode.