A tracking area identity list updating method for updating a tracking area identity list in a communication system which includes: a terminal; a mobility management entity that executes processing relating to the terminal; and a plurality of serving gateways (40,50), wherein the plurality of serving gateways are classified into a control plane that is a route through which a control signal for a communication service used by the terminal is transmitted, and a user plane that is a route through which a user signal for the communication service is transmitted, and the terminal is connected to a plurality of user planes and retains information on tracking areas corresponding to service areas of the user planes as a tracking area identity list, wherein, when the terminal is connected to the plurality of the user planes, the terminal retains information on tracking areas in which service areas of the plurality of user planes overlap as the tracking area identity list, and the tracking area identity list updating method comprises: a step of transmitting information identifying a tracking area after movement and an update request of the tracking area identity list to the mobility management entity, by the terminal, when the terminal moves to the outside of tracking areas described in the tracking area identity list, or a step of transmitting an update request of the tracking area identity list to the mobility management entity, by the terminal connected to the one or more user planes, when the terminal is connected to a new user plane or cuts off a connection with the user planes to which the terminal is connected; a step of creating a new tracking area identity list corresponding to an overlapping portion of service areas of the plurality of user planes and in which the tracking area after movement is considered as a service area or a step of creating a new tracking area identity list corresponding to an overlapping portion of service areas in the plurality of user planes after updating based on the update request overlap; and a step of notifying the terminal of the new tracking area identity list for updating a current tracking area identity list, by the mobility management entity, on the basis of the update request. a step of transmitting information identifying a tracking area after movement and an update request of the tracking area identity list to the mobility management entity, by the terminal, when the terminal moves to the outside of tracking areas described in the tracking area identity list, or a step of transmitting an update request of the tracking area identity list to the mobility management entity, by the terminal connected to the one or more user planes, when the terminal is connected to a new user plane or cuts off a connection with the user planes to which the terminal is connected; a step of creating a new tracking area identity list corresponding to an overlapping portion of service areas of the plurality of user planes and in which the tracking area after movement is considered as a service area or a step of creating a new tracking area identity list corresponding to an overlapping portion of service areas in the plurality of user planes after updating based on the update request overlap; and a step of notifying the terminal of the new tracking area identity list for updating a current tracking area identity list, by the mobility management entity, on the basis of the update request.