Component mounting method in component mounting system

An external set-up device calculates a shift amount of a supply position of a component which is supplied by a tape feeder that is disposed on the carriage. The storage stores supply position shifting data in which the shift amount of the component supply position is related to a feeder address and a feeder ID. The component mounter compares the feeder ID of the tape feeder with the feeder ID included in the component supply position shifting data which is read from the storage, and, in a case in which the feeder IDs do not match, calculates the shift amount of the component supply position of the corresponding tape feeder and updates the supply position shifting data. The component mounter mounts the components onto a board based on the updated component supply position shifting data.