An exhaust purification system comprising: an oxidation catalyst provided in an exhaust passage of an internal combustion engine; a pair of first and second filters (22, 23) provided in the exhaust passage at positions downstream of the oxidation catalyst to collect particulate matter contained in exhaust gas; electrostatic capacity detecting means configured to detect an electrostatic capacity of the first filter; accumulation amount estimating means configured to estimate an amount of accumulated particulate matter at least in the second filter based on the electrostatic capacity entered from the electrostatic capacity detecting means; and filter regenerating means configured to execute a forced regeneration to burn and remove the particulate matter that has accumulated at least in the second filter by injecting fuel to the oxidation catalyst when the amount of accumulated particulate matter entered from the accumulation amount estimating means exceeds a predetermined amount, characterized in that the exhaust purification system further comprises: internal temperature estimating means configured to estimate an internal temperature of the first filter based on the electrostatic capacity entered from the electrostatic capacity detecting means; and injection amount correcting means configured to correct a fuel injection amount of the filter regenerating means based on a temperature difference between a filter target temperature in a forced regeneration and the internal temperature entered from the internal temperature estimating means. an oxidation catalyst provided in an exhaust passage of an internal combustion engine; a pair of first and second filters (22, 23) provided in the exhaust passage at positions downstream of the oxidation catalyst to collect particulate matter contained in exhaust gas; electrostatic capacity detecting means configured to detect an electrostatic capacity of the first filter; accumulation amount estimating means configured to estimate an amount of accumulated particulate matter at least in the second filter based on the electrostatic capacity entered from the electrostatic capacity detecting means; and filter regenerating means configured to execute a forced regeneration to burn and remove the particulate matter that has accumulated at least in the second filter by injecting fuel to the oxidation catalyst when the amount of accumulated particulate matter entered from the accumulation amount estimating means exceeds a predetermined amount, characterized in that the exhaust purification system further comprises: internal temperature estimating means configured to estimate an internal temperature of the first filter based on the electrostatic capacity entered from the electrostatic capacity detecting means; and injection amount correcting means configured to correct a fuel injection amount of the filter regenerating means based on a temperature difference between a filter target temperature in a forced regeneration and the internal temperature entered from the internal temperature estimating means. internal temperature estimating means configured to estimate an internal temperature of the first filter based on the electrostatic capacity entered from the electrostatic capacity detecting means; and injection amount correcting means configured to correct a fuel injection amount of the filter regenerating means based on a temperature difference between a filter target temperature in a forced regeneration and the internal temperature entered from the internal temperature estimating means.