PURPOSE: To generate a multiple conversation program of high reliability by extracting data items used in each transaction as save items at the time of referring to these data items in some position in the program.

CONSTITUTION: A transaction recognizing part 21 recognizes an inputted multiple conversation program as plural transactions, and a data item extracting part 23 extracts used data items and refered data items in each transaction from the multiple conversation program. A save item extracting part 25 takes out data items referred in the program based on data items referred by each transaction and extracts common items of used data items and data items referred in the program of each transaction as save items. Thus, save items are automatically extracted to generate the multiple conversation program of high reliability.