To provide a hydraulic control device for a construction machine capable of preventing the working performance from dropping in the altitude operations while the durability of the engine components is well secured.

The hydraulic control device of the construction machine is equipped with an engine 1, at least one hydraulic pump 3 of variable displacement type driven by the engine 1, at least one actuator 7 driven with the discharge oil of the pump 3, an exhaust gas temperature sensor 13 to sense the temperature t of the exhaust gas from the engine, a controller 12 to control the operating pilot pressure Px produced by a solenoid proportional decompression valve 11 in accordance with the sensing result of the sensor 13, and a regulator 5 to control the rate of discharge flow Q so as to limit the maximum of the input torque T of the pump 3 in accordance with the operating pilot pressure Px.