<p>Provided is a fatigue test device that makes it possible to calculate a target waveform for a servo amplifier that enables to give a desired operation to works. The fatigue test device converts input waveform data for at least one discrete period to a fluctuation waveform spectrum of a deformation amount of the works and generates initial spectrum data; multiplies each spectrum component of the initial spectrum data by a correction coefficient to generate first spectrum data and obtains the first spectrum data; carries out a reverse conversion of the first spectrum data to obtain test waveform data and imposes a load on test works based on the test waveform data; obtains output waveform data to show fluctuation of a deformation amount of the test works on which the load is imposed; converts the output waveform data to a fluctuation waveform spectrum of the deformation amount of the test works to obtain second spectrum data; and revises the correction coefficient based on each frequency spectrum component of the input spectrum data and a frequency spectrum component corresponding to the second spectrum data.</p>
