PURPOSE: To automatically determine inboard stowage constitution of an iron and steel product according to an experience and perception of a skilled expert.

CONSTITUTION: When ship information and product information are inputted (502 and 503), the determination (504) of an outline, the determination (505) of product stowage and the adjustment (506) of a weight balance are performed according to a previously created rule based on an experience and a perception of a skilled expert. Ship information is preserved in a ship data base 110, and product information is preserved in a product data base 109. Products to be shipped are classified by loading places and kinds, and the approximate arrangement is determined as a product group, and a weight balance when being stowed with every single product is also adjusted, and stowage constitution is determined. The determined stowage constitution is registered (507) in a stowage result data base 111, and when an output demand is inputted (508), it is outputted as a stowage block diagram.