An abnormality detection apparatus for a filter comprising: a filter that is provided in an exhaust passage of an internal combustion engine to trap particulate matter in exhaust gas; a catalyst that is provided in the exhaust passage and removes NOx with supply of HC; an HC supply unit that supplies HC to the catalyst; a PM sensor that detects particulate matter in the exhaust gas at a location downstream of the filter and the catalyst and outputs a signal representing the particulate matter deposited in the PM sensor; a determination unit that is configured to determine whether or not the filter has an abnormality, on the basis of an output value of the PM sensor; and a control unit that is configured to cause the HC supply unit to supply HC to the catalyst, characterized in that the control unit is configured, while particulate matter is made to deposit in the PM sensor in order for the determination unit to determine whether or not the filter has an abnormality, to cause the HC supply unit to supply HC to the catalyst in such a way as to make the quantity of heat generated in the catalyst smaller when the temperature around the PM sensor is higher than a prescribed temperature than when the temperature around the PM sensor is lower than the prescribed temperature, or when the flow speed around the PM sensor is higher than a prescribed flow speed than when the flow speed around the PM sensor is lower than the prescribed flow speed, whereby preventing or reducing the rise in the temperature of the exhaust gas when the temperature around the PM sensor is higher than the prescribed temperature or when the flow speed around the PM sensor is higher than the prescribed flow speed. a filter that is provided in an exhaust passage of an internal combustion engine to trap particulate matter in exhaust gas; a catalyst that is provided in the exhaust passage and removes NOx with supply of HC; an HC supply unit that supplies HC to the catalyst; a PM sensor that detects particulate matter in the exhaust gas at a location downstream of the filter and the catalyst and outputs a signal representing the particulate matter deposited in the PM sensor; a determination unit that is configured to determine whether or not the filter has an abnormality, on the basis of an output value of the PM sensor; and a control unit that is configured to cause the HC supply unit to supply HC to the catalyst, characterized in that the control unit is configured, while particulate matter is made to deposit in the PM sensor in order for the determination unit to determine whether or not the filter has an abnormality, to cause the HC supply unit to supply HC to the catalyst in such a way as to make the quantity of heat generated in the catalyst smaller when the temperature around the PM sensor is higher than a prescribed temperature than when the temperature around the PM sensor is lower than the prescribed temperature, or when the flow speed around the PM sensor is higher than a prescribed flow speed than when the flow speed around the PM sensor is lower than the prescribed flow speed, whereby preventing or reducing the rise in the temperature of the exhaust gas when the temperature around the PM sensor is higher than the prescribed temperature or when the flow speed around the PM sensor is higher than the prescribed flow speed.