In a telephone system, a memory dial mode is set by operating a mode key of a radio telephone, and then a selection key is manipulated to select a public telephone number of an opposite (called) radio telephone. Thereafter, when a dialing key is operated, a dialing output process to the public telephone number selectively displayed on a LCD (liquid crystal display) unit is performed. When a telephone ending key is operated while a telephone line is not connected, a private telephone number of the radio telephone previously stored into a RAM is displayed on the LCD unit. Subsequently, when the dialing key is operated, another dialing output process to the private telephone number displayed on the LCD unit is executed.