A mobile telephone device includes: a communication switching unit that selectively switches between an LTE communication system and a CDMA communication system, for performing communication; and a determination unit which, upon communication initiation being requested in a situation where a location registration is performed in the LTE communication system, determines whether or not the communication initiation is of a predetermined communication type; wherein if it is determined that the communication initiation is not of the predetermined communication type, the communication switching unit changes a location registering destination by giving priority to the LTE communication system after communication is completed in the CDMA communication system, and if it is determined that the communication initiation is of the predetermined communication type, the communication switching unit continues the location registration to the CDMA communication system even after the communication is completed in the CDMA communication system.