This position paper proposes a new concept of "Assurance as Code". Society has become increasingly complex, and many systems are interconnected (system of systems), so that a small bug can cause a major system failure. The need to describe assurance cases to improve system reliability is increasing, but the cost of describing assurance cases is very high. The solution to this problem is to develop an environment in which programmers can freely write assurance cases like program code. Just as the idea of "Infrastructure as Code (IaC)" enabled easy infrastructure construction with the help of gamification, this has the potential to make it easy for nonspecialists to write assurance cases. The author is working on prototyping such an environment and outlines its current status and challenges.