A technique for performing message communications while assigning a space and respective time periods or time points at present, in past and in future is disclosed. A space-time object intercepts a message. Alternatively, this object per se executes the processing for immediately transmitting a message to a target object under management with relevancy thereto, for retaining the message by a future time point assigned, or for preparing and sending a message for searching logs in the past, thereby to realize the space-time communications.