An optimization processing computer, before production starts, sends a production job on which optimization processing was performed but is incomplete to each component mounter, causes an automatic exchanging device to operate so as to change the feeder arrangement of each component mounter to a feeder arrangement specified in the production job, then causes each component mounter to operate so as to start production. After production is started, optimization processing on the production job is continued by the optimization processing computer, and during production, an updated production job for which optimization has progressed is acquired from the optimization processing computer so as to update the production job being executed by each component mounter, then the automatic exchanging device is operated so as to change the feeder arrangement of each component mounter to a feeder arrangement specified in the production job, then production continues.