A heating furnace includes a target space (212a) in which a burning target is disposed, and a furnace main body (212) that surrounds the target space. The heating furnace includes one or more closed gas heaters having an introduction hole configured to introduce a fuel gas into the main body, a combustion chamber in which the introduced fuel gas is combusted, a discharge section to which an exhaust gas generated by combustion is guided, a radiation surface heated by the exhaust gas flowing through the discharge section or combustion in the combustion chamber and configured to transfer radiant heat to the burning target, and an exhaust hole configured to exhaust the exhaust gas that heats the radiation surface to the outside of the main body, and disposed in the furnace main body, and an exhaust heat transfer section (an insulated pipe (222a)) in communication with the exhaust hole of the closed gas heater and to which the exhaust gas is guided. In addition, the exhaust heat transfer section is installed at any portion in the furnace main body except for a radiation space (212b) formed between the closed gas heater and the burning target disposed in the target space and configured to transfer the radiant heat to the burning target.