On transition of a 1x system from a standby state in which standby processing is performed to out of service state in an SHDR mode, the standby processing for the 1x system using a receiver unit (RX1) is halted and, when an instruction to switch from a call through an EVDO system using a transmitter-receiver unit (RX0/TX) and/or the receiver unit (RX1) to a call through the 1x system using the transmitter-receiver unit (RX0/TX) during the halt state is detected, a system detection process for detecting the 1x system is performed by using the receiver unit (RX1).