Abstract: In a medical image data managing system, a directory managing unit is employed so as to manage directory data on overall medical image data. The medical image data managing system comprises: a plurality of modality units for producing medical image data in accordance with sorts of the modality unit a plurality of database units for storing at least the medical image data produced from the modality units: workstation units for issuing a demand to fetch desirable medical image data from the database units and for displaying the fetched medical image data; and, a directory managing unit for storing directory information about to which database units the desirable medical image data has been stored and for outputting the directory information upon receipt of the demand issued from the workstation means.