PURPOSE: To obtain the file reconstitution processing method which performs the transaction processing of the real-time information processing system in parallel to operation without deteriorating the performance of the transaction processing.

CONSTITUTION: This file reconstitution method is equipped with a transaction processing part 1 which performs the transaction processing of the real-time information processing system, a 1st file 2 and a 2nd file 3 stored with record data, a file control table 4 which indicates the file wherein record data requested to be processed is present, and a file reconstitution processing part 5 which performs file reconstitution for transferring record data before deletion processing for removing unnecessary record data to the 2nd file 3 when unnecessary record data after the deletion processing are collected in the 1st file 2. Consequently, the transaction processing and file reconstitution processing are put in parallel operation.