To ensure the same administrative improvement as that by a company's merger or the like, between different companies or between different business departments of the same company, while maintaining identity of each company or the like.

A business entity information storage part 10 manages business segment data on a plurality of business entities so that they are shared. Upon a request for business execution, business segment extracting means 30 are executed to extract a business segment suitable for the business execution. Efficient business execution is thus possible regardless of the belonging business entities, so that without a company merger, restructuring or the like, the same administrative improvement as that by a company merger or the like can be ensured while identity of each company or the like is maintained.