An information delivery system is disclosed which is under control of one real estate agent and delivers information about real estate handled by the one real estate agent via an Internet or the like to terminal units belonging to other real estate agents admitted by the one real estate agent respectively. The system includes a delivery information data base storing a plurality of pieces of information about real estate to be delivered to the terminal units, a terminal unit data base storing a mail address, telephone number and another communication address for the terminal units, a narrowing condition data base storing narrowing conditions set for every one of the other real estate agents, and a delivering unit narrowing the information about the real estate stored by the delivery information data base on the narrowing conditions for every one of the real estate agents for delivering, to the terminal unit stored by the terminal unit data base, the narrowed information about real estate.