An exhaust gas treatment method including: (A) a step of treating exhaust gas from cement manufacturing equipment by using a dust collector 9 to collect dust containing chlorinated organic compounds, and discharging the exhaust gas after the treatment by the dust collector 9, and (B) a step of charging all or part of the dust collected by the dust collector 9 into a place (e.g. a rotary kiln 5, a pre-calciner 6, and a cyclone 4d) having a temperature of at least 800 C. inside the cement manufacturing equipment. The remainder of the dust from step (B) maybe charged into a place (e.g. a raw material supply passage 3) having a temperature below 800 C. inside the cement manufacturing equipment, provided the amount of the remainder to be charged is smaller than a certain amount. Chlorinated organic compounds such as dioxins in the exhaust gas can be decomposed efficiently to be made harmless, merely by including simple and low-cost means (e.g. a dust feeding means 12, etc.).