The utility model discloses a detection apparatus for power failure. Detection device is including awaiting measuring cable and test device, and wherein, test device includes: the voltage regulator for adjust the line voltage of input, testing transformer is connected respectively with the voltage regulator and the cable that awaits measuring for to the voltage boost after adjusting through the voltage regulator, and the voltage output after will stepping up to the cable that awaits measuring, wherein, voltage regulator, testing transformer integration are in test device, and there is the relation of connection in each part among the test device. The utility model provides a because power cable's trouble testing equipment is more in the correlation technique, the wiring is complicated, leads to the circuit to connect the mistake easily, causes the technical problem that testing equipment burns out.