The present invention provides a data management apparatus (i-Win (trademark)) which carries out centralized management of data containing data on each product during the management of product data having different data items to be handled and which has increased maintenance-ability in system and program(s).A data storage part 13 stores transaction data (contract data) including class ID (logic key) and data contents ID (variable). A data definition part 17 records data contents IDs and data contents (clause data) for each clause ID. A data processing means 15 acquires combination data of a data contents ID and data content from the data definition part 17 (definition body) in accordance with a class ID recorded in the data storage part 13 and performs processing which relates to data contents of a predetermined data item (contract condition). In this way, centralized management of plurality of product data having different product features from its clause and prospectus and the like can be carried out.