Process of value creation has been mainly described by the concept of value chain, but platforms are becoming new important basis of value creation. However, value creation on platforms may not be sustainable if platformers will monopolize the profit. The concept of value co-creation on business ecosystem supports the idea that platformers and suppliers of complementary products and services are interdependent and share the profit. Suppliers also can be the sources of innovation on ecosystem. We applied this idea to the elder care business in Japan, and proved that this idea is helpful to promote innovations and provide solutions in important issues like elder care.