To provide a means for supporting a user in determining data to be clustered by previously estimating a clustering effect in a data storage management device for controlling the physical storing position of a data group to be stored in a database.

This management device is provided with a data retrieving means 1 for retrieving plural data having applied relation from a data group mutually related based on management information and stored in a storage device, a data length integrating means 2 for integrating the data length of the retrieved data, a data distribution recording means 3 for recording the distribution of storing positions of the retrieved data in the storage device in each previously set storing section unit, and a clustering evaluation means 4 for evaluating an effect for clustering plural retrieved data based on the number of storing section units storing the retrieved data and the integrated data length.