Regeneration abnormality determination device for particulate filter

A device for determining any regeneration abnormality of a particulate filter having an oxidation catalyst in front thereof, fuel being added upstream of said oxidation catalyst by a fuel addition valve to undergo oxidation reaction on said oxidation catalyst, whereby resultant reaction heat makes forced regeneration of burning off captured particulates, comprising a temperature sensor for detecting an exhaust temperature on an entry side of said particulate filter and a controller for feedback controlling an injection amount, by said fuel addition valve, of the fuel to be added on the basis of an actually measured value by said temperature sensor within a predetermined temperature range around said target regeneration temperature so as to keep the exhaust temperature on the entry side of said particulate filter to the target regeneration temperature upon the forced regeneration, said controller being configured to simulatedly calculate the exhaust temperature on the entry side of the particulate filter on the basis of a commanded injection amount to said fuel addition valve and determine any abnormality of the feedback control on the basis of a deviation between the calculated exhaust temperature on the entry side of the particulate filter and the actually measured value by said temperature sensor.