The third choice is to register the alternative component in the component mounting system 1. That is, although an error does not occur in the supply reel 14A that reads the component ID or the supply reel 14B prepared by the operator, the alternative component accommodated in the supply reel 14B may not be previously registered in the component mounting system 1, that is, the component data 20 and the component group data 21 regarding the alternative component may not be created. In this case, the component arranging operation supporting apparatus 4 determines as the comparison NG in spite of the fact that the alternative component can be used as an alternative to the master component. In such a case, the operator can register the alternative component in the component mounting system 1 by performing the alternative component registering process by the component arranging operation supporting apparatus 4. A method of registering the alternative component will be described below.

When the comparison result is the comparison OK in the component comparing process (ST4) described above, the control unit 24 notifies the mounting machines M1 to M3 of the comparison OK (arrow c shown in FIG. 4) (ST6: second comparison result notifying process). When the alternative component is replenished as in the present example, the control unit 24 notifies that the mounting target has been changed to the alternative component from the master component.