To prevent a construction machine from being stolen by disabling travel or work outside a preset working time.

A hydraulic pressure circuit for the construction machine comprises a main hydraulic pressure circuit containing a main pump, an actuator to be driven by a pressure oil from the main pump and a direction changing valve for controlling the direction of hydraulic pressure to the actuator, a pilot hydraulic pressure circuit containing a pilot pump and a pilot valve for guiding pilot pressure to the direction changing valve, and a controller for various control. A timer is built in the controller for identifying a working time zone, an solenoid selector valve is inserted into the pilot hydraulic pressure circuit or the main hydraulic pressure circuit, and the solenoid selector valve is connected to the controller. When an engine is started within a preset working time zone, the solenoid selector valve is not energized by the controller and is kept in an open (communicating) condition, and when the engine is started outside the preset working time zone, the solenoid selector valve is energized by the controller and is kept in a closed (shutoff) condition to shut off the supply of the pressure oil.