Abstract: An automatic delay-controlling device for pre-setting a delay of the switching-on or switching-off of loads such as general motors, lighting apparatuses, etc., having a controller, a central processing unit, a read only memory, an address multiplexer, a programmable peripheral interface, an ouput driver and an alternating-current power supply connected to the output driver via a load. The controller is connected to the central processing unit and has three buttons serving as inputs to the central processing unit for inputting the duration of the delay. The central processing unit, read only memory, address multiplexer and programmable peripheral interface are intercommunicated to co-process signals from the controller in order to control the operation of the output driver. Therefore, the output driver is controlled to carry or not carry the load with the aid of the alternating-current power supply.