To describe all programs absolutely necessary for the operation of an automatic machine by describing parallel execution processing and interruption processing or the like by extending a flow chart while making the best of the advantages of the flow chart suitable for the description of the program of sequence control such as sequence processing.

This system is provided with a tool region 62 on which new components being elements for describing a program as a flow chart are mounted and a plotting region 64 for preparing the flow chart by using the new components, and the new components are constituted of at least one of parallel execution components 68 and parallel execution stand-by components 69 making a pair with the parallel execution components 68, interrupting components 67, and sub-routine components 96 in which a sub-routing program is describable.