Electronic musical apparatus (EMA), e.g. an electronic musical instrument, has a storage area for storing a unique ID; however, unique ID is empty in the storage area in an initial condition, e.g. condition at the time of shipment from a factory. Unique ID is issued by a Web server to the EMA when a user having acquired the EMA accesses a predetermined Web site having an ID issuing function, and the EMA stores the supplied unique ID in the storage area. The Web server determines whether or not any unique ID has already been issued to a given EMA having accessed the Web site, and, if not yet issued, the Web server may automatically issue a unique ID. Alternatively, the Web server may issue a unique ID when an ID issuance request has been received from a user of the EMA. User registration operation and unique ID issuance and registration operations may be carried out together as a set of operations.