To provide a full-year air conditioning facility using a heating device using a boiler unit for cooling operation without double equipment investment such that a new cooling device is installed separately from the heating device using the boiler unit and incidental piping.

In a heat medium circuit between a boiler unit and a heat radiation apparatus of the existing heating device through which a heat medium heated by the boiler unit having a circulation pump and a boiler is circulated into the heat radiation apparatus, a switch is newly provided for circulating either the heat medium heated by the boiler unit or the heat medium cooled with heat exchange in a ground. A ground heat exchange unit for cooling the heat medium with heat exchange in the ground and a second circulation pump for circulating the cooled heat medium are connected to the switch. During cooling operation, the heat medium cooled with the heat exchange in the ground is circulated through the switch into the heat radiation apparatus.