The purpose of this study is to define a method of building an integrated service to provide various science and technology knowledge infrastructures that are helpful in R&D activities, and to show the cases that are adapted the methodologies. Knowledge infrastructures scattered throughout the entire R&D cycle, such as generating/development of ideas, finding the R&D project, performing the project, and spreading results, are segmented in terms of services, functions, information, and data, and links and converges to provide the knowledge infrastructure that desired by users in one place. We define the integrated service classification, integration level model, integrated architecture, and integrated user authentication system in consideration of logical linkage and integration rather than physical integration of individual knowledge infrastructures. Also, we considered the extensibility as the reference model for building of similar integrated service.