A working machine comprising: a diesel engine; a variable displacement hydraulic pump driven by the diesel engine; exhaust gas treatment equipment having a filter capturing particulate matter in the exhaust gas of the engine; cooling water temperature detecting means for detecting cooling water temperature of the engine; load control means for increasing at least one of revolution speed of the engine, displacement volume (q) and discharge pressure of the hydraulic pump from a state at low-idle time to increase an engine load; regeneration control means for compulsorily regenerating the filter by allowing fuel to stay in the exhaust gas of the engine to compulsorily elevate exhaust temperature; and regeneration instruction means for instructing the regeneration control means to start the compulsory regeneration; wherein the load control means is configured to keep, after the instruction is given by the regeneration instruction means to start the compulsory regeneration and when the cooling water temperature is lower than flame-out prevention temperature set to prevent occurrence of flame-out during the compulsory regeneration, at least one of the revolution speed of the engine, the displacement volume (q) and discharge pressure of the hydraulic pressure pump at a corresponding first target value (N1, q1, or P1) set to allow the cooling water temperature to reach the flame-out prevention temperature or higher, and in that the load control means is configured to keep after the instruction is given by the regeneration instruction means to start the compulsory regeneration and when the cooling water temperature is equal to or higher than the flame-out prevention temperature, at least one of the revolution speed of the engine, the displacement volume (q) and discharge pressure of the hydraulic pressure pump at a corresponding second target value (N2, q2, or P2) that is a target value set to keep exhaust temperature at which the compulsory regeneration is possible and that is set lower than the first target value, and in that the regeneration control means is configured to start the compulsory regeneration after the instruction is given by the regeneration instruction means to start the compulsory regeneration and when the cooling water temperature is equal to or higher than the flame-out prevention temperature. a diesel engine; a variable displacement hydraulic pump driven by the diesel engine; exhaust gas treatment equipment having a filter capturing particulate matter in the exhaust gas of the engine; cooling water temperature detecting means for detecting cooling water temperature of the engine; load control means for increasing at least one of revolution speed of the engine, displacement volume (q) and discharge pressure of the hydraulic pump from a state at low-idle time to increase an engine load; regeneration control means for compulsorily regenerating the filter by allowing fuel to stay in the exhaust gas of the engine to compulsorily elevate exhaust temperature; and regeneration instruction means for instructing the regeneration control means to start the compulsory regeneration; wherein the load control means is configured to keep, after the instruction is given by the regeneration instruction means to start the compulsory regeneration and when the cooling water temperature is lower than flame-out prevention temperature set to prevent occurrence of flame-out during the compulsory regeneration, at least one of the revolution speed of the engine, the displacement volume (q) and discharge pressure of the hydraulic pressure pump at a corresponding first target value (N1, q1, or P1) set to allow the cooling water temperature to reach the flame-out prevention temperature or higher, and in that the load control means is configured to keep after the instruction is given by the regeneration instruction means to start the compulsory regeneration and when the cooling water temperature is equal to or higher than the flame-out prevention temperature, at least one of the revolution speed of the engine, the displacement volume (q) and discharge pressure of the hydraulic pressure pump at a corresponding second target value (N2, q2, or P2) that is a target value set to keep exhaust temperature at which the compulsory regeneration is possible and that is set lower than the first target value, and in that the regeneration control means is configured to start the compulsory regeneration after the instruction is given by the regeneration instruction means to start the compulsory regeneration and when the cooling water temperature is equal to or higher than the flame-out prevention temperature.