In the requirements definition phase, conceptual models are used to understand the developing software. Although scenarios are often described on the basis of conceptual models, there are cases that necessary requirements are omitted in the scenarios when the scenarios are created manually. Herein we propose an approach to support scenario creation from conceptual models where event lists of scenarios, which include checkpoints to define requirements, are generated from conceptual models automatically. The conceptual models represent the core resources of the software, the owner of the core resources, and use cases as class diagrams. Then software engineers and their clients arrange the event lists and define requirements as scenarios on the basis of the checkpoints. Our approach can support describing scenarios with all the necessary requirements from conceptual models. To confirm the effectiveness of our approach, we compared our approach to the all-manual approach.