An apparatus for multi-terminal communication service includes a service determination unit configured to determine use or non-use of a mobile communication service by a main communication terminal or an auxiliary communication terminal corresponding to the main communication terminal, a terminal determination unit configured to determine a communication terminal among the main communication terminal and the auxiliary communication terminal, which does not use the mobile communication service, and a service changing unit configured to change a type of the mobile communication service to be provided to the determined communication terminal. The mobile communication service includes a data communication service and the use or non-use of the data communication service is determined based on information from a DPI (Deep Packet Inspection) or a charging device.