An issue to be settled by the present invention is to define a simulation model in accordance with the structure of a causal relation easy to be understood by human and to shorten greatly a simulation program development period. A simulation program is automatically generated by extracting, as nodes, specific items such as phenomenon, events and targets of constituent elements of economy, society or the like regarded as a system, coupling the nodes with arcs to define the structure of the causal relation, and defining a variable necessary for calculating metrics and a calculation formula therefor, relative to a simulation model inheriting the defined structure.