The utility model discloses an auxiliary tester for a spare power automatic switching device. The auxiliary tester comprises a switching-on indicating lamp, a switching-off indicating lamp, a hand-operated switching-on contact, a hand-operated switching-off contact, a switching-on terminal, a switching-off terminal, a power switch electric quantity indicator, a tripping and switching-on common terminal, an alternating current air switch I, an alternating current air switch II, and an alternating current air switch III fixed on a panel of a box body, and a direct current power supply and a double-coil relay fixed in the box body. According to the auxiliary tester, the size is small, the weight is low, the carrying is convenient, and the verification of common spare power automatic switching devices in the current substation can be satisfied.