To improve convenience in fault repair by displaying the disconnection and short circuit of an LNB or antenna cable.

A junction connector 2 is interposed between an LNB 1 and a cable 3. A resistor 11 of the junction connector has a divisor-multiple resistance value as high as a DC impedance of the LNB and a resistor 13 of a receiver 4 has a small resistance value. A voltage on both the terminals of the resistor 13 (proportional to a load current I) is inputted to a differential amplifier 14 and on the basis of an output signal, load normality, cable disconnection LNB disconnection and short circuit of the LNB or cable are determined by a CPU 15. Normally, both LED 17 and 18 of a display part 16 are turned off, in the case of cable disconnection, the LED 18 is turned on, in the case of LNB disconnection, the LED 17 is turned on and in the case of short circuit of the LNB or cable, both the LED 17 and 18 are turned on. In the case of load non-normality, the output of power supply to the load is stopped and the display on the display part is held.