Recently, as IT Compliance becomes more diverse, companies have to take a great amount of effort to comply with it and prepare countermeasures. Especially, E-Discovery is also one of the most notable compliances for IT and law. In order to minimize the time and cost for E-Discovery, many service systems and solutions using the state-of-the-art technology have been competitively developed. Among them, Cloud Computing is one of the most exclusive skills as a computing infrastructure for E-Discovery Service. Unfortunately, these products actually do not cover all kinds of E-Discovery works and have many drawbacks as well as considerable limitations. This paper, therefore, proposes a new type of E-Discovery Service Structure based on Cloud Computing called EDaaS(E-Discovery as a Service) to make the best usage of its advantages and overcome the limitations of the existing E-Discovery solutions. EDaaS enables E-Discovery participants to smoothly collaborate by removing constraints on working places and minimizing the number of direct contact with target systems. What those who want to use the EDaaS need is only a network device for using the Internet. Moreover, EDaaS can help to reduce the waste of time and human resources because no specific software to install on every target system is needed and the relatively exact time of completion can be obtained from it according to the amount of data for the manpower control. As a result of it, EDaaS can solve the litigant�s cost problem.