POWER SUPPLY DEVICE

There is provided a power supply apparatus capable of supplying information as a power line communication signal superimposed on a voltage of a commercial frequency, although currents of the commercial frequency are not supplied to power receiving side external equipment, and capable of supplying power to a specific external apparatus together with the power line communication signal, by controlling supply of the currents of the commercial frequency to the external apparatus. This apparatus includes at least a power receiving section that receives the supply of the power from a power line; a power line communicating section that superimposes the power line communication signal on the voltage, which is supplied to the power receiving section, and transmits the power line communication signal to the equipment; and a power supply limiting section which is installed between the power receiving section and the equipment, allows the power line communication signal to pass and limits the supply of the power to the equipment.