An exhaust gas purification apparatus comprising: a pre-oxidation catalyst which burns an unburned constituent contained in exhaust gas of an engine by catalysis; a particulate filter which is arranged downstream of the pre-oxidization catalyst to collect soot contained in the exhaust gas; a heating device which increases an amount of the unburned constituent to be supplied to the pre-oxidation catalyst to perform a active regeneration of the particulate filter; a first soot-accumulation calculation unit which calculates a first soot accumulation amount in the particulate filter from a first index, the first index being an operation state of the engine; a second soot-accumulation calculation unit which calculates a second soot accumulation amount from a second index, the second index being different from the first index and being at least one of a total operation time of the engine, a total fuel consumption rate, or a pressure difference between front and back of the particulate filter; a regeneration starting unit which determines a starting of active regeneration when either one of the first soot accumulation amount and the second soot accumulation amount, respectively, reaches a regeneration start threshold value; the exhaust gas purification being characterized by a first soot-accumulation correction unit which corrects the first soot accumulation amount calculated by the first soot accumulation calculation unit to a value greater than the first soot-accumulation amount when the starting of the active regeneration is determined by the regeneration starting unit based on the second soot accumulation amount calculated by the second soot-accumulation calculation unit; and a regeneration ending unit which ends the active regeneration when, in such a case that the active regeneration starts based on the corrected soot accumulation amount corrected by the first soot-accumulation correction unit, the first soot accumulation amount becomes less than a threshold value of ending the regeneration. a pre-oxidation catalyst which burns an unburned constituent contained in exhaust gas of an engine by catalysis; a particulate filter which is arranged downstream of the pre-oxidization catalyst to collect soot contained in the exhaust gas; a heating device which increases an amount of the unburned constituent to be supplied to the pre-oxidation catalyst to perform a active regeneration of the particulate filter; a first soot-accumulation calculation unit which calculates a first soot accumulation amount in the particulate filter from a first index, the first index being an operation state of the engine; a second soot-accumulation calculation unit which calculates a second soot accumulation amount from a second index, the second index being different from the first index and being at least one of a total operation time of the engine, a total fuel consumption rate, or a pressure difference between front and back of the particulate filter; a regeneration starting unit which determines a starting of active regeneration when either one of the first soot accumulation amount and the second soot accumulation amount, respectively, reaches a regeneration start threshold value; a first soot-accumulation correction unit which corrects the first soot accumulation amount calculated by the first soot accumulation calculation unit to a value greater than the first soot-accumulation amount when the starting of the active regeneration is determined by the regeneration starting unit based on the second soot accumulation amount calculated by the second soot-accumulation calculation unit; and a regeneration ending unit which ends the active regeneration when, in such a case that the active regeneration starts based on the corrected soot accumulation amount corrected by the first soot-accumulation correction unit, the first soot accumulation amount becomes less than a threshold value of ending the regeneration.