In electronic conference systems, a terminal operation system prevents a conflict of operations to a plurality of processing objects displayed on a shared screen of an operated terminal, enhances smooth proceeding of the conference and realizes easier operation. An operating terminal and an operated terminal are connected via a network, and an operation authority is set on a shared screen display device of the operated terminal by each AP or window as an unit for processing objects. The operation authority is managed with an operation authority managing table in an operation authority managing portion, which controls the active processing objects and operates input operation from the operating terminal having the operation authority and the processing objects via an operation input accepting portion. Conditions can be set with respect to acquiring operation authorities and making them effective. The operated terminal also plays a roll as one operating terminal by acquiring the operation authority as one operating terminal under an equal condition.