An energy-saving power socket with slave power supply, especially a power socket having plural receptacles, with power supply of part of the receptacles depending upon a working condition of a master receptacle of primary load that the slave receptacles are turned off when an electric appliance which takes electricity from the primary load receptacle stops working, primarily connects an end of an electronic control circuit to a manual switching device, an end of which is connected to the slave receptacles. When the control circuit operates, the slave receptacles will be guided to supply electricity, depending upon the working condition of the master receptacle. In addition, the control circuit does not consume electricity while not working.