This is a system of filing a PCT application to the Patent Office (Receiving Office) of the country of origin or the country of residence in which the patent is filed, and then entering the national phase into the country (Designated (Selected) State) in which an applicant wants to obtain a patent within a specified period. The PCT international filing date can be recognized as the filing date in the designated country. However, in the case where the application is filed claiming priority of the prior application, a priority claim may be recognized when a PCT international application is filed within 12 months from the filing date of the earlier application.