PURPOSE: To identify a cause for an abnormal operation by detecting in the sintering operation an abnormality in permeability and a variation in sinter point that are abnormalities in operation and inspecting whether or not there are variations in various factors that influence the variation in the permeability in raw materials for sintering and burning point at a specified time before the time of the abnormality detection.

CONSTITUTION: Powdered iron ore, coke, etc., are dispensed from respective raw material tanks 1 in a specified volume and they are transported to a drum mixer 6 through a conveyor 4, and here water is added and they are mulled to form a sintering raw material. And this sintering raw material is loaded to a pallet 9 from a supply ore hopper 5 and in the state of ignition by an ignition furnace 16 air is sucked to wind boxes 12 and the burning section S is moved downwards. In this operation a control unit 23 detects an abnormality in permeability and variation in a burning point, and it is inspected whether or not there are various factors that influence the permeability in the sinter raw materials and the variation in the burning point at the time before the time of the abnormality detection by specified time and causes of abnormal operation are identified.