Order handling apparatus of the present invention stores assembly standard information that at least one component is managed for each assembly and component standard information which is basic information of a component to be mapped with each other. Order handling apparatus duplicates component standard information together with assembly standard information to generate individual assembly information for arranging an assembly, assigns arranging formation representing whether a component is arranged or not to generate individual component information and stores them. Order handling apparatus determines whether to reflect an update of component standard information in component standard information contained in individual assembly information based on arranging information when component standard information stored in standard assembly storing unit is updated.