PURPOSE: To only designate an incoming predeterminate time to surely complete transmission by this time by calculating the time required for transmission and starting transmission at the time obtained by subtracting the time required for transmission from the incoming time.

CONSTITUTION: When an information incoming time is designated by a designating means 3 and a transmission condition is inputted from an input means 2, a control means 4 calculates the time required for information transmission based on the inputted transmission condition. A transmission means 1 is so controlled that transmission is started at the time obtained by subtracting the time required for transmission from the incoming time. Thus, the transmission means 1 starts information transmission at the transmission start time, and transmission of all information to the transmission destination is completed by the incoming time.