PURPOSE: To perform an efficient test, by a method wherein a fatigue life is evaluated at the same time as a rotary testing result of an equipped machinery.

CONSTITUTION: Oil in an oil tank 4 is increased in pressure by means of a pump 10, and a hydraulic ram 11 is actuated by oprating a controller 8 and an electromagnetic relief valve 7 in synchronism with a tester displacement input 9. An object to be tested is secured to a jig 12 in which an interpolar connecting copper belt 3 is attached to a teste body. A load equivalent to a centrifugal force is applied below the jig 12 trough the hydraulic ram 11, an abutting plate 13, and a rubber pad 14. If one side of the jig 12 is secured and the other is repeatedly applied with a tensile displacement, and this enables changing of a voltage value showing a displacement input of a tester, and of the oil pressure in the hydraulic ram 11. If the controller 8 is adjusted so that a load, being equivalent to a centrifugal force load, is applied at a maximum displacement time equal to a rated rotation time, it provides with hysteresis of a displacement and centrifugal force load similar to an equipped machinery.