To provide an evaluation device for fatigue damages, capable of easily diagnosing fatigue damages of a structure.

The evaluation device 10, for fatigue damages mounted at prespecified measurement portions of the structure, for evaluating fatigue damages, includes an accelerator 21 for measuring the amount corresponding to a single day of acceleration data of a measurement portion, and a data process section 24 for detecting a dominant frequency and a daily maximum acceleration range based on displacement data measured by the accelerator 21, estimating the frequency distribution of a stress range based on the dominant frequency and the daily maximum acceleration range, and further evaluating the fatigue damages of the structure, where all of these elements have been integrated.