In this paper, we introduce a new language AWL of workflow diagrams for requirement analysis in large scale information system developments. AWL has a merit that one can describe concrete and accurate life cycles of evidences (evidence documents) in workflow diagrams in the language. We also introduce a tool AWDE that supports users to compose consistent workflow diagrams in AWL, by visualizing life cycles of evidences in the workflow diagrams and verifying consistency of the life cycles. As a validation of AWL and AWDE, we report an experiential result in requirement analysis in real large scale information system developments with and without AWDE.