An exhaust treatment device for a diesel engine, including a diesel particulate filter, an exhaust gas temperature sensor for detecting a temperature of an exhaust gas on an upstream side of the diesel particulate filter, an intake throttle valve, control means, and memory means; wherein: a target temperature of the exhaust gas on the upstream side of the diesel particulate filter, a first valve opening degree of the intake throttle valve, and set durations (T1, T2, T3, T4) for stages of exhaust gas temperature rise processing are stored in the memory means, in the regeneration of the diesel particulate filter by burning and removing particulate matter, accumulated on the diesel particulate filter, by using heat of the exhaust gas, the control means performs a first stage of the exhaust gas temperature rise processing, a target rotation number of the engine being set in said first stage to a predetermined first target rotation number and an opening degree of the intake throttle valve being set to the first valve opening degree; if the temperature of the exhaust gas on the upstream side of the diesel particulate filter does not reach the target temperature and the set duration of the first processing stage has elapsed, the control means performs a second processing stage wherein the target rotation number of the engine is maintained at the first target rotation number and the opening degree of the intake throttle valve is more closed than the first valve opening degree; and if the temperature of the exhaust gas on the upstream side of the diesel particulate filter does not reach the target temperature and the set duration of the second processing stage has elapsed, the control means performs further processing stages (P3, P4) of the exhaust gas temperature rise processing, wherein in these stages(P3,P4) the opening degree of the intake throttle valve is maintained at a second valve opening degree, corresponding to the opening degree reached at the time when the set duration of the second processing stage has elapsed, until the temperature of the exhaust gas on the upstream side of the diesel particulate filter reaches the target temperature, and the temperature of the exhaust gas on the upstream side of the diesel particulate filter is raised by updating the target rotation number of the engine into target rotation numbers (R2,R3), each higher than each of the target rotation numbers (R1,R2) of the preceding stages (P2,P3), based on an elapse of the set durations (T3, T4) of the further processing stages (P3, P4). a target temperature of the exhaust gas on the upstream side of the diesel particulate filter, a first valve opening degree of the intake throttle valve, and set durations (T1, T2, T3, T4) for stages of exhaust gas temperature rise processing are stored in the memory means, in the regeneration of the diesel particulate filter by burning and removing particulate matter, accumulated on the diesel particulate filter, by using heat of the exhaust gas, the control means performs a first stage of the exhaust gas temperature rise processing, a target rotation number of the engine being set in said first stage to a predetermined first target rotation number and an opening degree of the intake throttle valve being set to the first valve opening degree; if the temperature of the exhaust gas on the upstream side of the diesel particulate filter does not reach the target temperature and the set duration of the first processing stage has elapsed, the control means performs a second processing stage wherein the target rotation number of the engine is maintained at the first target rotation number and the opening degree of the intake throttle valve is more closed than the first valve opening degree; and if the temperature of the exhaust gas on the upstream side of the diesel particulate filter does not reach the target temperature and the set duration of the second processing stage has elapsed, the control means performs further processing stages (P3, P4) of the exhaust gas temperature rise processing, wherein in these stages(P3,P4) the opening degree of the intake throttle valve is maintained at a second valve opening degree, corresponding to the opening degree reached at the time when the set duration of the second processing stage has elapsed, until the temperature of the exhaust gas on the upstream side of the diesel particulate filter reaches the target temperature, and the temperature of the exhaust gas on the upstream side of the diesel particulate filter is raised by updating the target rotation number of the engine into target rotation numbers (R2,R3), each higher than each of the target rotation numbers (R1,R2) of the preceding stages (P2,P3), based on an elapse of the set durations (T3, T4) of the further processing stages (P3, P4).