To solve the problem of conventional testing methods needing large- scale testing apparatuses and very complicated maintenance.

This testing apparatus comprises a stator 2 with no rotor arranged in it as a load of an inverter or servo driver 1, and a current detector 5 for detecting current flowing into the stator 2. The apparatus is capable of automatically detecting abnormal operations of the inverter or the servo driver, by attaching a function of comparing the current value detected by the current detector 5 with the specified current value of the inverter or the servo driver, and producing an error signal, if the detected current value deviates from the specified current value. The stator 2 has no rotor in it, and it is under a static load condition. It is thus possible to facilitate controlling of the value of current flowing into the stator 2, by regulating speed command voltage and controlling the output voltage of the inverter or the servo driver 1.