To provide a method of an a system for supporting creation of improvement structure to reduce member costs, assembly costs, and losses associated with defective assemblies of a product. Parts constituting a product are analyzed into functions, attributes, assembly operations, and assembly attributes; on the basis of the difference between the member and assembly costs due to presence or absence of these elements, elements requiring improvement are extracted; and improvement guidelines are created using similar improvement examples in the past. It is possible to present improvement guidelines in structure to reduce the member costs and the assembly costs.