Previous study has investigated that, unlike most other fields, patent literatures are not regarded as a knowledge sources for the conception of new inventions in software field. This result shows a possibility of Japanese patent law’s laying open system is not functioning in this field. Therefore, we have conducted a survey to one of the top Japanese companies in this field which has high priority on patent activity. We have investigated that inventors who have rich experience and achievements, regard patent literatures as knowledge sources for the conception of new inventions. We also found that “high-ability searchers” and “high quality reading comprehension skill” are the key factors for the success to make outstanding engineers.