PURPOSE: To reduce labor for preparing layout and to shorten time for the preparation by preparing a layout idea corresponding to a production plan based on production processes, producing devices, production forms, the structure of production areas and position relation conditions calculated based on inputted data.

CONSTITUTION: A layout drawing data is prepared by describing the positions of various producing devices, conveying equipments and partitions, conveying paths and the partition of modules or the like into relevant positions on a layout drawing based on a prepared list data. On the other hand, numerical layout data such as a material handling distance, construction cost, equipment cost and productivity or the like obtained from the prepared layout drawing data are calculated, and plural layout idea data are prepared while pairing the layout drawing data and the numerical layout data. Then, the layout idea data having the maximum value of totalizing the evaluation exponents of respective items is selected as the optimum layout idea data. Thus, labor for preparing the layout is reduced and time for the preparation is shortened.