In an information distribution service system comprising a plurality of mobile information terminals, a computer system and a plurality of information-provider terminals, the computer system is provided with a user-information database for registration information categories provided for the mobile information terminals' users each serving as a recipient of an information distribution service rendered by the information distribution service system, an information-provider database for registering locations of the information-provider terminals and information to be distributed by the information-provider terminals as notifications, and a location management unit provided for the purpose of inferring changes in location of each mobile information terminal in a time series by using an inference formula provided in advance for predicting the particular mobile information terminal's moving direction and location on the basis of information on locations of the particular mobile information terminal.