In a server-client network conference system having a conference server 100 and a plurality of conference terminals 140a to 140n through a network 130, a conference data storage section 120 creates a real-time conference data file 123 and an index file 122 containing time-of-day information and heading information while a conference proceeds. After the conference is over, edit such as voice stream merge processing, image thinning-out processing, etc., in the real-time conference data file 123 is performed to create a minute file 124 and the minute file 124 is managed with an index file 122.