Method for removing ash from the particulate filter

A sufficiently suppress the pressure loss of the particulate filter. An excess oxygen in the combustion under is disposed in an exhaust passage of an internal combustion engine to be performed, the wall flow type particulate filter for collecting particulate matter in the exhaust gas, the particulate filter using a supported solid acid, a method for removing ash, the state of the particulate filter, the oxygen concentration of the inflow exhaust gas to the particulate filter is lowered and a state in which the temperature is increased of the particulate filter to. Then, the state of the particulate filter, a state that contains SOx in the inflowing exhaust gas to the particulate filter under an oxidizing atmosphere. .FIELD 1