Abstract: It is an object of the present invention to provide a portable telephone in which external sound can be used as a call receiving sound and a pause of sound can be avoided even when the switching operation of a base station is generated during reproducing the call receiving sound. Sound picked up by a microphone (180) is subjected to an AD conversion, then encoded by an ADPCM system in an encoding part (141) and stored in an ADPCM encoded data storing area (150b). The stored audio data of a partner to talk with is encoded by the ADPCM system in the encoding part (141) via a digital audio signal processing part (122) and stored in the ADPCM encoded data storing area (150b). Upon receiving a call, the stored data is read, decoded to an analog audio signal in a decoding part (142) and outputted as the call receiving sound from a speaker (181) via an audio output circuit (136).