PURPOSE: To improve the throughput of on-line processing by exclusively releasing a file by the on-line transaction processing system according to priority levels which are provided, medium by medium.

CONSTITUTION: This system has a file exclusive release priority transaction classified registration means 9 which can register the priority levels of exclusive release of files, wherein the priority levels of exclusive release of updated files can be registered by each transaction, a file exclusive release priority level storage means 10 which stores the registered file exclusive release priority levels, a file exclusive release priority level reference means 11 which refers to the stored file exclusive release priority levels, and a file exclusive releasing means 8 which releases the exclusion of the updated files according to the file exclusive release priority.