To prevent a foaming ratio from being degraded in a high expansion foam extinguishing facility used in a pit of an oil tank, a culvert of an oil industrial complex, a cabin or a boathouse or the like and its foaming method.

The high expansion foam extinguishing facility comprises a foaming part 3 provided with a net 7 for foaming and radiation nozzles 9 and an air suction part 5 for supplying air in a discharge section 1 to the foaming part 3. The air suction part 5 is provided with a heater 10 for evaporating smoke.