1. A production system including a production line being a series of a plurality of pieces of production equipment each of which has a parts supply unit, the production system comprising: an NC management apparatus that is connected with each piece of the production equipment via a local-area network and acquires therefrom NC data used for operating each piece of the production equipment; and a scheduling apparatus that generates a production schedule and transmits the generated production schedule to the NC management apparatus via the local-area network, wherein the NC management apparatus generates, for each piece of the production equipment, data that is required to perform production according to the production schedule, obtains, for each piece of the production equipment, differences between current NC data that has been acquired the most recently and the generated data, and outputs the obtained differences.