In this paper, we propose and develop a security scanner with high portability and usability. Recently, illegal access has been increasing explosively. Not only experts but also beginners need to cope up with vulnerability of a system promptly and properly. In such cases, a security scanner is an efficient tool to point out the vulnerability. However, for general users, most of the presently available security scanners are hard to install and operate because they have considerably poor usability. We have developed a security scanner with high usability, called USAGI. USAGI is a Web based security scanner, therefore it should not depend on operating systems, and should not need any installation. However, web based scanners cannot inspect a host which cannot issue a scan request such as internet appliance. Moreover, a web based scanner is not effective for a host inside firewall, if one would like to check vulnerability against insider threat. To overcome these problems, we design a portable version of USAGI, while keeping high usability. We adopted Perl and Macromedia Flash for development of the security scanner to realize portability. Since all the scanning processes are performed only by a few mouse clicks, our security scanner can be implemented on a small handheld computer without keyboard. In functionality, we have realized high extensionality and reliability by using the external script of Nessus.