A refrigerant cycle (16) for cooling as a prototype is provided with: an internal condenser (8) connected to a discharge circuit of an electric compressor (9) and disposed on a downstream of an internal evaporator (7) of an HVAC unit (2); a first heating circuit (18) connected to a receiver (11) through a switching unit (17) arranged on an inlet side of the external condenser (8); and a second heating circuit (23) connected between an outlet side of the receiver (11) and a suction side of the electric compressor (9) and provided with a second expansion valve (20) and an external evaporator (21). A heat pump cycle (24) for heating is formed by a second heating circuit (23) including the electric compressor (9), the internal condenser (8), the switching unit (17), the first heating circuit (18), the receiver (11), the second expansion valve (20), and the external evaporator (21).