PURPOSE: To facilitate explicating trouble causes by managing the execution of an application program for every transaction and preserving the state at the start time of each transaction.

CONSTITUTION: When an application program 2 is executed, a transaction management part 3 discriminates the first transaction 6 of the application program 2 and starts it, and register values, etc. at the start time of the transaction 6 are stored in a buffer 10 to preserve the start at the start time of the transaction 6. If the transaction 6 is terminated normally, this normal end is reported to the management part 3. Data, updated data, etc. to be delivered to a transaction 7 to be started next are stored in the buffer 10. If the transaction is terminated abnormally on the way, a transaction recovery part 4 is started, and register values, etc. at the start time which are stored in the buffer 10 are transferred, and required data are transferred form an auxiliary storage device 12, and the program is restored to the state at the start time.