Multiple component mounters connected via a network are able to have multiple units attached. A control device of each component mounter requests other component mounters to send the specific information and the update date and time of a unit corresponding to the unit ID read by an ID reading section from an ID recording section of the unit set on the component mounter, and in certain cases a request is sent to the other component mounters to send the specific information of the unit, and the specific information of the unit and the update date and time of the specific information sent from the other component mounter in accordance with the request are stored in the storing section of the component mounter that issued the request.