To enable control capable of following the sudden combustion change accompanied by the fluctuations of the refuse quality of waste and to stabilize the temp. of the exhaust gas inlet of a dust collector.

In a control method of the temp. of the exhaust gas inlet of the dust collector of waste melting equipment, the temp. of the exhaust gas inlet of the dust collector 9 is fed back to operate the control quantity of the spray water amt. of an exhaust gas cooling device 8 and the temp. of the exhaust gas of the outlet of a waste heat recovery boiler and the flow rate of flue exhaust gas are used to calculate the quantity of heat of the exhaust gas flowing in the exhaust gas cooling device 8 and the control quantity of the spray water amt. of the exhaust gas cooling device 8 is operated from the calculated quantity of heat of the exhaust gas and the control quantities of two calculated spray water amts. are added to obtain control quantity and the spray water amt. of the exhaust gas cooling device 8 is regulated on the basis of the control quantity by a flow rate regulator 15.