To provide a method and a system for contract for flaw guarantee responsibility insurance in construction industry, which can be easily and smoothly achieved through series of procedures on a communication network.

In the contract method for flaw guarantee responsibility insurance, with which an insurance company makes an insurance contract on the condition of the issue of a written guarantee from a material maker or the like to construction property, the system is provided with a server, which is communicable and ahs a retrieval system, other communicable builder computer, computer of a company performing construction work, material maker server and insurance company computer and after the selection data of material/construction work specifications are determined, while utilizing order sheet data, shipping request sheet data, shipping certificate date, site confirmation sheet generated corresponding to the generation of the shipping request sheet data and the shipping certificate data, site confirmation sheet data, written guarantee issue request sheet data and written guarantee issue notice data, the insurance company computer sends the input processing instruction of written guarantee issue notice data to the server. Then, the server sends the written guarantee issue notice data to the insurance company computer.