To provide a baking furnace under a special atmosphere.

In this baking furnace under the special atmosphere generating erosive gas such as Pb or Bi during baking process, an alumina-silica-based insulating refractory containing not less than 70 wt.% of Al2O3 and not more than 30 wt.% of SiO2 is used for an innermost wall, and the alumina-silica-based insulating refractory containing not less than 90 wt.% of Al2O3 and not more than 10 wt.% of SiO2 is used for a second heat-insulating layer which is an erosive gas absorbing layer and reduces the temperature down to a freezing and deposition temperature. The wt.% of Al2O3 the second heat-insulating layer is at least higher than that of the innermost wall, or a zirconia, magnesia or spinel refractory is used for the second heat-insulating layer.