To provide a client terminal for data maintenance capable of continuing equipment data maintenance even when a failure occurs in communication between a data management server for unitary management of equipment data for each operation location and a client terminal for data maintenance at each operation location.

A client terminal for data maintenance comprises: a maintenance unit for maintaining equipment data; an equipment data storage unit for storing equipment data updated by maintenance; a master data update request unit for requesting the data management server to update master data of the equipment data stored in the data management server on the basis of the equipment data updated by the maintenance; and a management area storage unit having a management area for managing the request for updating the master data from the data update request unit.