To provide a portable telephone whose display on its display device is limited, while the telephone is in service to reduce power consumption and the hardware of an existing portable telephone need not be changed significantly, and convenience for a user is maintained.

A CPU 1 detects a service state according to the establishment and cut-off of call of the service, and if it is detected that the telephone is in service, the display on a display device 2 is limited, to put into a power savings mode in which little power is consumed.