This paper presents a requirement analysis, design, and implementation of ISEE: an information security engineering environment. ISEE integrates various tools and functions for supporting continuous and consistent design, development, management, maintenance, and abolition of security facilities of information systems with high security requirements, and forces users to perform their tasks according to ISO standards and a regular sequence. We defined requirements for ISEE to achieve continuous and consistent design, development, management, maintenance, and abolition of security facilities. We also designed ISEE according to the requirements, and implemented some tools of ISEE. Users of ISEE can ensure the whole security of a system by continuously and consistently performing their tasks.