An exhaust purification device for an internal combustion engine which is provided with: a particulate filter which is arranged inside of an engine exhaust passage for trapping particulate matter which is contained in exhaust gas, which particulate filter is provided with alternately arranged exhaust gas inflow passages and exhaust gas outflow passages and porous partition walls which separate these exhaust gas inflow passages and exhaust gas outflow passages from each other, wherein in each partition wall, a coated zone where a coated layer with an average pore size which is smaller than the average pore size of a partition wall substrate is used to cover the substrate surface and a non-coated zone at the downstream side of the coated zone and where the substrate surface is not covered by said coated layer, are defined and wherein the pore size of each partition wall is set to 25 μm to 50 μm so that the ash which is contained in the exhaust gas can pass through the partition wall in the non-coated zone, the exhaust purification device being characterised in that it is further provided with: a judging means for performing judgment processing which judges if a particulate matter trapping rate of the particulate filter has fallen below an allowable lower limit value; and a PM removing means for performing PM removal processing which removes particulate matter from the particulate filter when it is judged that the particulate matter trapping rate of the particulate filter has fallen below the allowable lower limit value. a particulate filter which is arranged inside of an engine exhaust passage for trapping particulate matter which is contained in exhaust gas, which particulate filter is provided with alternately arranged exhaust gas inflow passages and exhaust gas outflow passages and porous partition walls which separate these exhaust gas inflow passages and exhaust gas outflow passages from each other, wherein in each partition wall, a coated zone where a coated layer with an average pore size which is smaller than the average pore size of a partition wall substrate is used to cover the substrate surface and a non-coated zone at the downstream side of the coated zone and where the substrate surface is not covered by said coated layer, are defined and wherein the pore size of each partition wall is set to 25 μm to 50 μm so that the ash which is contained in the exhaust gas can pass through the partition wall in the non-coated zone, the exhaust purification device being characterised in that it is further provided with: a judging means for performing judgment processing which judges if a particulate matter trapping rate of the particulate filter has fallen below an allowable lower limit value; and a PM removing means for performing PM removal processing which removes particulate matter from the particulate filter when it is judged that the particulate matter trapping rate of the particulate filter has fallen below the allowable lower limit value. a judging means for performing judgment processing which judges if a particulate matter trapping rate of the particulate filter has fallen below an allowable lower limit value; and a PM removing means for performing PM removal processing which removes particulate matter from the particulate filter when it is judged that the particulate matter trapping rate of the particulate filter has fallen below the allowable lower limit value.