The present disclosure provides a fatigue management system capable of managing fatigue of each portion of a construction machine more accurately than conventional systems. The fatigue management system S includes: a stress calculation section S1 that calculates stress acting on a plurality of portions of the construction machine based on the output of a sensor 18 attached to a part of the construction machine; a damage degree calculation section S2 that calculates the cumulative damage degree of each portion of the construction machine based on the stress calculated by the stress calculation section S1; and an index value calculation section S3 that calculates a fatigue index value, which is a weighted value of the cumulative damage degree, for each portion.