To extract only a required signal by restoring a signal to each signal before multiplexing even after signals are multiplexed and recorded.

A CDMA(code division multiplexing access) code allotting device 2 allots CDMA codes to sound signals A, B and C from plural sound sources 1a, 1b and 1c, and forms signals including respective codes. After these signals are multiplexed by a multiplexing device 4, a sound recording device 5 records it in a digital source 3. In the case of editing, an editing device 11 discriminates the desired signal from the multiplexed signal recorded in the digital source 3 by using a CDMA code allotted to the desired signal, extracts it, and performs the editing. In the case of reproduction, a reproducing device 7 discriminates the desired signal from the multiplexed signal recorded in the digital source 3 by using the CDMA code allotted to the desired signal and extracts it to perform reproduction. Thereby, even after signals are multiplexed and recorded, they can restore to each signal before multiplexing, thus only the desired signal can be extracted, edited and reproduced.