To provide an engine load control device attached to an existing hydraulic device to simply control the engine load.

A discharge circuit 5 of a hydraulic pump 4 for driving a hydraulic actuator 7 is provided with a safety valve 10, an unload valve 11 for regulating the delivery pressure of the hydraulic pump 4 according to the load of the hydraulic actuator 7, and a displacement control valve 13 for controlling the delivery. A communicating circuit 21 is provided for communicating the discharge circuit 5 to a load detecting circuit 14 for transmitting the load of the hydraulic actuator 7 to the unload valve 11 and the displacement control valve 13. The communicating circuit 21 is provided with a solenoid on-off selector valve 31, a first restriction 24 and a one-way valve 24 serially disposed toward the load detecting circuit 14. A drain branch circuit 25 is provided between the first restriction 24 and the one-way valve 24, and the circuit is provided with a pressure control valve 27. An engine temperature sensor 33 and the on-off selector valve 31 are connected to each other through a controller 34.