This invention aims to attain an industrial furnace which ensures uninterrupted operation of itself and protects accessorial devices thereof including a rotary regenerative burner against otherwise possible damage when the rotary regenerative burner suffers from a mechanical trouble, and possess high responsivity and high accuracy. This industrial furnace has an oxidizing agent passage (12) communicating with-an oxidizing agent duct (33a) of a rotary regenerative burner (30), an exhaust gas passage (13) communicating with an exhaust gas duct (33b), a bypass (15) allowing intercommunication between the oxidizing agent passage (12) and the exhaust gas passage (13), and cut-off valves (16, 17) provided respectively in the bypass (15) and the exhaust gas passage (13), whereby the cut-off valve (16) on the bypass (15) side and the cut-off valve (17) on the exhaust gas passage (13) is controlled in response to a signal from burner.