An automatic production line control data forming system for use in a production design, control and preparation system for a production line comprising: a process planning system for inputting data such as configurations and tolerances which are provided on drawings, and performing a process planning operation with reference to production machine data; a production scheduling system for making day's schedule plans; and an automatic programming system for forming programs for production machines such as NC machine tools and robots. In the automatic production line control data forming system, configuration data and machining features of parts which have been formed during process planning are subjected to formal conversion and transmitted to the automatic programming system, to allow the automatic programming system to form NC programs; or the kinds, the numbers and the delivery dates of parts to be manufactured during a given period which are provided as an article production plan, and data on production machines for machining the parts and machining time therefor which are formed during process planning are subjected to formal conversion and transmitted to the production scheduling system, to allow the production scheduling system to form day's schedule plans.