A device for grouping elements included in a system structure; e.g., devices or application programs, when preparing a system structure definition, and flexibly determining the parameters of the elements on the basis of the group structure is provided with: a structure definition storage means for storing a system structure definition including multiple elements that are the parameters set as setting categories for defining the structure of the system; a rule storage means for storing rules including identifiers for first and second setting categories; a grouping means for dividing the elements into groups on the basis of the parameters of the second setting category of the elements; and an assignment execution means for setting and outputting parameters that are the same or unique within a group for the first setting category of each element in a group.
