PURPOSE: To improve the thermal efficiency of a glass smelting apparatus furnished with a regenerator or a recuperator, by utilizing the hot exhaust gas of the glass smelting furnace furnished for the preheating of the glass raw material and the combustion air using ceramic spheres as a heat medium.

CONSTITUTION: Hot gas 5 exhausted from the glass smelting furnace 1 is heat- exchanged and accumulated in the regenerator 3. A part of the gas discharged from the regenerator 3 is introduced into the ceramic sphere pre-heater 8 to the ceramic spheres used as the heat medium. A part of the heated ceramic sphere is introduced into the secondary air preheater 9 to preheat the secondary air 4. The preheated secondary air is further heated in another regenerator 2 of the smelting furnace 1, and used as the combustion air for the furnace 1. The remaining part of the ceramic spheres is utilized for the preheating of the raw material glass batch 16 in the rotary heat-exchanger 10, and returned to the ceramic sphere preheater 8. The remaining part of the exhaust gas discharged from the regenerator 8 is transferred to the glass cullet preheater 15 and utilized for the preheating of the raw material glass cullet.