Build to order (BTO) systems are generally used as systems for corporate to manage production or systems for the consumers to customize components. This paper discusses the BTO system for consumers which can decide the specifications easily. The present BTO systems for personal computers can customize a construction of the personal computers on the web in compliance with users' requests. However, there are many expert consumers who feel that the BTO systems are not satisfy with their requests because components of PC prepared in the system are not many enough to choose. In contrast, beginner users do not have enough knowledge of making selection PC components; therefore it is very difficult for them to use the systems without mistaking. This research develops a BTO system built on the web that includes an information database on a huge number of various PC components and a function that can choose the combination of PC components automatically. As a result, expert users can make a PC of best performance capabilities. Moreover, beginner users become possible to select a construction of the PC easily and automatically only by providing the purpose and the budget.