To provide a controlling method of a circulating volume of exhaust gas, whereby a blowing out of the exhaust gas containing carbon monoxide to outside of a hood, is prevented in a sintering operation by circulating of the exhaust gas, and the sintering operation by circulating of the exhaust is safe and stable.

The circulating volume of the exhaust gas to be introduced in a hood is controlled by arraying a pressure gauge 1 in the plural number of positions where a flow and a pressure of gas in the hood are apt to change, and by arranging the opening degree of a damper installed in a circulating system and the rotational speed of a blower 8 so that the maximum value of pressure showed by those above pressure gauges is in the range of values of design pressure as an operating condition.