To instantaneously draw up an optimum layout plan from an equipment D/B and to exhibit the plan on the spot after inputting customer's requirement or the like in an estimate or PR stage of a plant, and to enable order placement of equipment as it is.

The customer's requirement or various conditions are inputted by a data input section 2, latest information about each the equipment is stored in a plant component information section 3 directly connected to a database of each maker of plant constitution equipment or connection equipment therefor, and is provided to a portable terminal device 1. Optimum constitution equipment according to the various conditions is selected in a plant component selection section 4, and the optimum arrangement plan is produced in a plant component arrangement plan production section 5. A material amount/amount of money in estimate arrangement is calculated in a material amount/amount of money calculation section 6, and the optimum plant component arrangement plan and the material amount/amount of money are displayed in a display section 7 by use of a three-dimensional model. As a result, for order reception, the order placement can be rapidly executed to each equipment maker from information about the equipment used for an estimate, in an order placement section 8.