This study attempts to look into business model design in the influence of entrepreneur opportunity. Through the case of Ready and Start as a social venture, this study explored how entrepreneur opportunity (social opportunity) influences each component (value proposition, value creation, value capture) design of a social venture business model. It identified that some elements of business model are designed for the necessary function of business model, some components and functions reflect the identified social opportunity: they are designed to take a key role to realize the identified social opportunity. Thus, this study noticed that social opportunity influences each component design of a social venture business model. Regarding value proposition, the result indicates that social opportunity take a role of defining the scope of market offerings and design the content of a social venture market offerings. A social venture could have customers as well as recipients of its market offering. This study indicates that the efforts to solve social problems helped define the concept of customer and recipient as well as distinguish between them. In terms of value creation, the results highlight that a social venture’ entrepreneur opportunity influence the acquisition of key resources and the construction of key processes to need to realize the identified social opportunity. With respect to value capture, the influence of social opportunity is unclear. However, when a social venture designs its profit model, this study noticed that a social venture could put an emphasis on social problem solving rather than on profit pursuit. Those evidences indicate that social opportunity differently influences each component design of a social venture business model. This study could have some theoretical and practical implications of business model innovation and entrepreneurship.