A mobile communication method according to the present invention comprising, a step in which a mobile station transmits a first location registration request signal including capability information indicating that it is compatible with a second radio access network, to a mobile switching center housing a first radio access network, a step in which the mobile switching center transmits a location registration rejection signal, which includes information indicating that communication using a second radio access network is not allowed, to the mobile station, a step in which the mobile station transmits a second location registration request signal, which includes capability information indicating that it is not compatible with the second radio access network, to the mobile switching center in response to the location registration rejection signal and a step in which the mobile switching center performs a location registration process with respect to the first radio access network of the mobile station in response to the second location registration request signal.