To provide a convenient, sanitary safety floor heating/cooling system excellent in durability, resource saving and thermal efficiency which can be installed easily on an arbitrary floor face without extreme temperature variation after stopping operation.

The floor heating/cooling system comprises a heat transmitting section 2 embedded with a heat radiation tube 6 and a metal mesh reinforcing material 7, a thermal insulation layer 8 of compressive sponge, a heat shielding layer 9 comprising an Ag foil laminated on the thermal insulation layer 8, a plywood 10 and a copper plate 11 laminated on the heat shielding layer 9, a space holding member 12 comprising thin wood rods arranged at a specified interval on the upper surface of the copper plate 11, and a thermally insulating supporting section 3 comprising an Ag foil 13 arranged on the upper surface of the space holding member 12.