This invention provides a system for managing information in a format that can be used based on the international standard time and local time. Upon storing and managing information (150), a) the local time (121) of a predetermined area, b) a standard difference (122) as the difference between the international standard time and the standard time of the predetermined area, and c) a season difference (122) as the difference between the standard time and the local time of the predetermined area in a corresponding season are appended.