A plurality of music apparatus 10 to 30 such as an electronic musical instrument and a microphone apparatus are connected by wireless to a mixer apparatus 40. A Bluetooth module is adopted as wireless communication means to construct a piconet with mixer apparatus 40 functioning as a master and music apparatus 10 to 30 functioning as slaves. Audio signals and MIDI data from music apparatus 10 to 30 are transmitted by wireless to mixer apparatus 40 through isosynchronous communication procedure using Bluetooth modules 11, 21, 31, 41. In mixer apparatus 40, with regard to the MIDI data, music tone signals based on the MIDI data are produced, whereafter the produced music tone signals and the aforesaid audio signals transmitted by wireless are mixed. Wiring by means of cables between a plurality of music apparatus and a mixer apparatus is abolished, thereby eliminating the cumbersomeness of wiring and the restrictions accompanying the wiring.