Engine control device, and its control method

An engine control device includes an engine-driven variable displacement hydraulic pump, a hydraulic actuator driven by oil from the pump, a control valve which controls the oil discharged from the pump, and supplies the oil to and from the hydraulic actuator, pump displacement detecting means, command means for selecting and commanding variable command values, and setting means for setting a first target engine speed in accordance with a command value, and a second target engine speed lower than the first target engine speed based on the first target engine speed. When the pump displacement increases and exceeds a first predetermined pump displacement when the engine is controlled based on the second target engine speed, a target engine speed is changed from the second target engine speed to a third target engine speed higher than the second target engine speed and equal to or lower than the first target engine speed.