A remote control device for controlling a watercraft propulsion device of a watercraft having an engine that generates propulsive power can have a plurality of remote control device side ECUs. All of the plurality of remote control device side ECUs can have the same construction. Each remote control device side ECU can have an ECU discriminating terminal section, an ECU determining section configured to determine a role of the respective remote control device side ECU based upon a signal provided from the ECU discriminating terminal section, and an exclusive use section configured to operate based upon a signal provided from the ECU determining section to execute a function corresponding to the role that is specifically assigned.