The cellular telephone device includes a reporting unit and a synchronization unit. In a case in which a communication request occurs in a 3G system in a state where the location registration is performed in an LTE system, the reporting unit reports the communication request, together with data for identifying the 3G system, to the LTE system. The synchronization unit receives synchronization information of a communication channel in the 3G system identified by the LTE system based on such data reported from the reporting unit, and establishes synchronization with the communication channel.