An engine system comprising: a diesel engine; an exhaust passage connected to the engine; a DPM filter provided on the exhaust passage, which traps diesel particulate matter contained in an exhaust gas such that the diesel particulate matter accumulates therein; a temperature adjusting device coupled to the engine, the temperature adjusting device adjusting an exhaust gas temperature of the engine; and a controller coupled to the temperature adjusting device, the controller functioning to: start regeneration processing of the DPM filter by controlling the temperature adjusting device to raise an exhaust gas temperature when a regeneration timing of the DPM filter is reached; set a target exhaust gas temperature during regeneration processing to ensure that a temperature of the DPM filter does not exceed an upper temperature limit of the DPM filter, even when the temperature of the DPM filter is raised due to the engine entering an idling condition during the regeneration processing; and control the temperature adjusting device to control the exhaust gas temperature to the target exhaust gas temperature, characterized in that the controller further functions to: estimate an accumulated DPM amount in the DPM filter; forecast a maximum temperature of the DPM filter when the engine switches to an idling operation during the regeneration processing; and set the target exhaust gas temperature during regeneration processing in accordance with the estimated accumulated DPM amount such that the forecast maximum temperature of the DPM filter does not exceed the upper temperature limit of the filter. a diesel engine; an exhaust passage connected to the engine; a DPM filter provided on the exhaust passage, which traps diesel particulate matter contained in an exhaust gas such that the diesel particulate matter accumulates therein; a temperature adjusting device coupled to the engine, the temperature adjusting device adjusting an exhaust gas temperature of the engine; and a controller coupled to the temperature adjusting device, the controller functioning to: start regeneration processing of the DPM filter by controlling the temperature adjusting device to raise an exhaust gas temperature when a regeneration timing of the DPM filter is reached; set a target exhaust gas temperature during regeneration processing to ensure that a temperature of the DPM filter does not exceed an upper temperature limit of the DPM filter, even when the temperature of the DPM filter is raised due to the engine entering an idling condition during the regeneration processing; and control the temperature adjusting device to control the exhaust gas temperature to the target exhaust gas temperature, start regeneration processing of the DPM filter by controlling the temperature adjusting device to raise an exhaust gas temperature when a regeneration timing of the DPM filter is reached; set a target exhaust gas temperature during regeneration processing to ensure that a temperature of the DPM filter does not exceed an upper temperature limit of the DPM filter, even when the temperature of the DPM filter is raised due to the engine entering an idling condition during the regeneration processing; and control the temperature adjusting device to control the exhaust gas temperature to the target exhaust gas temperature, characterized in that the controller further functions to: estimate an accumulated DPM amount in the DPM filter; forecast a maximum temperature of the DPM filter when the engine switches to an idling operation during the regeneration processing; and set the target exhaust gas temperature during regeneration processing in accordance with the estimated accumulated DPM amount such that the forecast maximum temperature of the DPM filter does not exceed the upper temperature limit of the filter. estimate an accumulated DPM amount in the DPM filter; forecast a maximum temperature of the DPM filter when the engine switches to an idling operation during the regeneration processing; and set the target exhaust gas temperature during regeneration processing in accordance with the estimated accumulated DPM amount such that the forecast maximum temperature of the DPM filter does not exceed the upper temperature limit of the filter.