A component mounting system includes at least one component mounter that is provided with a first board transport mechanism, a second board transport mechanism, a first mounting mechanism and a second mounting mechanism that mount components on a board, and a plurality of carriages that is respectively installed on the side of the first board transport mechanism and on the side of the second board transport mechanism and holds a plurality of tape feeders (component supply devices). When changing a production board type of a first board transported by the first board transport mechanism, the components are supplied from the component supply device held by a first carriage, a second carriage, and a third carriage, and the components are mounted on a second board that does not change the production board type by the first mounting mechanism and the second mounting mechanism.