In modern society, as the rapid development of IT technology combined with computer-based high-speed communication networks is enabling provision of a wide spectrum of services and devices, we have been confronted with a new era of cultural transformation, referred to as the information society. However, the security requirements that need to be considered have become more complicated and diversified, and the same security weaknesses exist as in the existing media or protocols. Particularly, an office network device with roaming is susceptible to different kinds of attacks such as terminal hacking, virus attacks, and information leakage, because the computing capacity is relatively low and the loading of already developed security functions is difficult. Although PKI security authentication technology was developed as one solution to this problem, it isn't suitable for multi-domain environments providing ubiquitous office network services, and so the development of a novel authentication system is needed. Therefore, this paper researched roaming and device authentication/authorization technology using an ID-based public key, authorization ticket, and sub-device ticket. The aim was to contribute to the development of secured and efficient technology.