Abstract: A portable apparatus is used to transmit wirelessly both musical accompaniment information, which includes music data of a plurality of music pieces and which is stored in an integrated circuit card, and a voice input from a user for reception and reproduction by an external speaker unit. The portable apparatus includes an elongated casing having a first end portion that is adapted to be gripped by one hand of the user and that confines a receiving space for receiving removably the integrated circuit card therein, and a microphone unit mounted on a second end portion of the casing for transforming the voice input from the user to a first electrical signal. A processor unit is disposed in the casing and is connectable electrically to the integrated circuit card. The processor unit is controlled by a keyboard, which is mounted on an intermediate portion of the casing, so as to transform the music data of a selected one of the music pieces into MIDI information.