A data management system includes a management apparatus including a processor, and plural storage devices. The processor is configured to generate hash values corresponding to data to be managed according to a predetermined calculation rule, the plural storage devices stores first hash values that are hash values generated by the processor at a first point in time, and the processor is configured to perform determination of invariance related to the plural first hash values or the data by comparing sets including the plural of first hash values read out from the plural storage devices and second hash values that are hash values regenerated according to the calculation rule at a second point in time later than the first point in time.