To provide a baking furnace superior in mass productivity, and capable of reducing the variation of product features, preventing the waste consumption of gas for atmospheric baking, and elongating the service life of a heater.

Furnace bodies 1, 2 have heating chambers 11, 21. The heaters 3, 4 heat the heating chambers 11, 21. Heat-proof tubular bodies 5 have baking chambers 51 into which the gas is introduced, and mounted through the heating chambers 11, 21. The heat-proof tubular bodies 5 are relatively movable to the furnace bodies 1, 2.